ACTIVE MATERIAL COMPOUND, MANUFACTURING METHOD FOR ACTIVE MATERIAL COMPOUND, AND SECONDARY LITHIUM B

专利摘要:
active material composite, manufacturing method for active material composite, and secondary lithium battery including active material composite. an active material composite including composite particles (3) and a solid sulfide-based electrolyte (4) is proposed. composite particles (3) contain particles of active material (1) and a solid oxide-based electrolyte (2). the active material particles (1) contain at least any one of a cobalt element, a nickel element and a manganese element and further contain a lithium element and an oxygen element. the solid oxide-based electrolyte (2) coats all or part of a surface of each of the active material particles (1). the solid sulfide-based electrolyte (4) still coats 76.0% or more of a surface of each of the composite particles.
公开号:BR112015018684B1
申请号:R112015018684-0
申请日:2014-02-06
公开日:2021-08-17
发明作者:Masahiro Iwasaki；Yusuke KINTSU
申请人:Toyota Jidosha Kabushiki Kaisha；
IPC主号:

专利说明:

BACKGROUND OF THE INVENTION 1, Field of Invention
[001] The invention relates to an active material compound that is capable of reducing a reaction resistance as compared to an existing active material compound when primarily used in a secondary lithium battery, a manufacturing method for the compound of active material, and a secondary lithium battery including the active material compound. 2. Description of Related Art
[002] Secondary batteries are not only capable of converting chemical energy into electrical energy and providing electrical energy (being discharged) but also capable of converting electrical energy to chemical energy and storing chemical energy (being charged) by passing a current in a direction opposite to this during discharge. Among secondary batteries, secondary lithium batteries have a high energy density, so secondary lithium batteries are widely used as power sources for mobile devices such as portable computers, personal computers and cell phones.
[003] In lithium secondary batteries, when graphite (denoted by C) is used as a negative electrode active material, the reaction expressed by the following formula (I) proceeds in a negative electrode during discharge.LixC6 -> 6C + xLi+ + xe_(In the formula described above (I), 0 < x < 1)
[004] Electrons produced from the reaction expressed in the formula described above (!) pass through an external circuit, work on an external charge and then reach a positive electrode. Lithium ions (Li*) produced from the formula described above (I) move within an electrolyte from the negative electrode side to the positive electrode side due to electroendosmosis. Electrolyte is held between the negative electrode and the positive electrode.
[005] When lithium cobalt oxide (LivxCoO ) is used as a positive electrode active material, the reaction expressed by the following formula (II) proceeds at the positive electrode during discharge. Li1xCoO2 * xLi+ * xe' - >LiCoO2 (II)(In the formula described above (II), 0<x<1)
[006]During discharge, the reverse reactions of the formula described above (I) and formula (II) respectively proceed on the negative electrode and the positive electrode, graphite (LixCe) in which lithium is intercalated by graphite intercalation is reproduced on the negative electrode , and lithium cobalt oxide (Lh-xCoOa) is reproduced on the positive electrode so that discharge becomes possible again.
[007] Electrodes that are used in secondary lithium batteries are important members that determine the charge/discharge characteristics of batteries, and several researches have been done so far. For example, Japanese Patent Application Publication 2010-073539 (JP 2010-073539 A) describes an electrode body that includes a positive electrode active material and a solid electrolyte. The positive electrode active material contains lithium cobalt oxide. A coating layer containing lithium niobate is formed on at least a portion of the lithium cobalt oxide surface. The solid electrolyte contains a solid sulfide. SUMMARY OF THE INVENTION
[008]JP 2010-073539 A describes that a positive electrode active material in which a layer of UNbO3 is formed on the LiCoO2 surface is mixed with Li7P3S11 (sulfide-based solid electrolyte) in the mass ratio of positive electrode active material: solid electrolyte = 7:3 to form a positive electrode (in paragraph 0038 in the specification of JP 2010-073539 A). However, as a result of a study conducted by the inventors, it has been found that a resistance to reaction is high because there are many positive electrode active material particles, not in direct contact with the solid sulfide-based electrolyte, in the electrode body in JP 2010-073539 A. The invention provides an active material compound which is capable of reducing a reaction resistance as compared to that of an existing active material compound when primarily used in a secondary lithium battery, a method of manufacturing for the active material composite, and a secondary lithium battery including the active material composite.
[009] A first aspect of the invention provides an active material compound. Active composite material includes: composite particles and a solid sulfide-based electrolyte. Composite particles contain particles of active material and a solid oxide-based electrolyte. Active material particles contain any one of a cobalt element, a nickel element and a manganese element, and further contain a lithium element and an oxygen element. Solid oxide-based electrolyte coats all or part of a surface of each of the active material particles. The solid sulfide-based electrolyte still coats 76.0% or more of a surface of each of the composite particles.
[010] In the active compound material according to the first aspect of the invention, the solid sulfide-based electrolyte can coat 85% or more and 95% or less of the surface of each of the composite particles.
[011] A second aspect of the invention provides a manufacturing method for an active composite material. The manufacturing method includes: a step of preparing composite particles containing active material particles and a solid oxide-based electrolyte, the active material particles containing at least any one of a cobalt element, a nickel element and a manganese element and further containing a lithium element and an oxygen element, the solid oxide-based electrolyte coating all or part of a surface of each of the particles of active material; and a step of coating a surface of each of the composite particles with a solid sulfide-based electrolyte by mixing the composite particles with the solid sulfide-based electrolyte with application of an energy, wherein the solid sulfide-based electrolyte is plastically deforms, while a temperature of a mixture of the composite particles and the solid sulfide-based electrolyte is set to 100°C or less.
[012] In the manufacturing method according to the second aspect of the invention, in the coating step, sulfide-based solid electrolyte particles having an average particle diameter of 1 µm or less can be used as the sulfide-based solid electrolyte .
[013] In the manufacturing method according to the second aspect of the invention, in the coating step, the solid sulfide-based electrolyte can be further added to the mixture after mixing for 10 minutes or more, and can be mixed with application of energy, in which the plasticity of the solid sulfide-based electrolyte deforms, while the temperature of the mixture is adjusted to 100°C or less.
[014] The manufacturing method according to the second aspect of the invention may further include a step of pre-treating the mixture in at least one of the sulfide-based solid electrolyte and compound particles with a compound having an alkyl group before of the coating step.
[015] A third aspect of the invention provides a secondary lithium battery. The secondary lithium battery includes a positive electrode; a negative electrode; and an electrolyte layer interposed between the positive electrode and the negative electrode. At least one positive electrode and the negative electrode contain at least one active material compound described above and the active material compound manufactured in accordance with the manufacturing method described above.
[016] According to aspects of the invention, by adjusting the coverage of the solid sulfide-based electrolyte on the surface of the composite particles to 76.0% or greater, it is possible to reduce the reaction resistance over time when used in a battery secondary lithium as compared to the existing active material composite. BRIEF DESCRIPTION OF THE DRAWINGS
[017] Characteristics, advantages and technical and industrial significance of the exemplary modes of the invention will be described below with reference to the accompanying drawings, in which such numerals denote such elements, and in which:
[018] FIG. 1A to FIG, 1D are cross-sectional views of active material compounds according to embodiments of the invention;
[019]FIG, 2 is a view showing an example of the layer configuration of a lithium secondary battery according to the invention, and is a view schematically showing the cross section taken in a laminated direction;
[020]FIG, 3 is a cross-sectional SEM image of an active compound material according to Example 13;
[021] FIG. 4A and FIG. 4B are surface SEM images of an active material composite according to Example 1;
[022] FIG. 5A and FIG. 5B are surface SEM images of an active material composite according to Example 2;
[023] FIG. 6A and FIG. 6B are surface SEM images of an active material composite according to Example 3;
[024] FIG. 7A and FIG, 7B are surface SEM images of an active material composite according to Example 4;
[025]FIG, 8A and FIG, 8B are surface SEM images of an active material composite according to Example 8;
[026] FIG. 9A and FIG, 9B are surface SEM images of an active material composite according to Example 9;
[027] FIG. 10A and FIG. 10B are surface SEM images of an active material composite according to Example 10;
[028] FIG. 11A and FIG, 11B are surface SEM images of an active material composite according to Example 11;
[029]F1G, 12A and FIG. 12B are surface SEM images of an active material composite according to Example 12;
[030] FIG. 13A and FIG, 13B are surface SEM images of an active material composite according to Example 13;
[031]FIG, 14A and FIG. 14B are surface SEM images of an active material composite according to Example 14;
[032]FIG, 15A and FIG. 15B are surface SEM images of an active material composite according to Reference Example 1;
[033]FIG, 16 is a graph showing the correlation between the coverage of each of the active material compounds for Example 1 to Example 14 and Comparative Example 1 and a kneading time in one coating step;
[034]FIG, 17 is a graph showing the correlation between the coverage of each of the active material compounds according to Example 4, Example 8, Example 10 to Example 14 and Comparative Example 1 and a reaction resistance of each of the secondary lithium batteries that use those composed of active materials;
[035] FIG. 18 is a schematic view of a Nyquist diagram that is obtained using a high-frequency impedance method;
[036] FIG. 19A and FIG. 19B are surface SEM images of an active material composite according to Comparative Example 1; and
[037]FIG, 20A and FIG. 20B are SEM images of natural graphite surface, DETAILED DESCRIPTION OF MODALITIES 1. Composite of Active Material
[038]An active material compound according to the invention includes: compound particles and a solid sulfide-based electrolyte. Composite particles contain particles of active material and a solid oxide-based electrolyte. The active material particles contain at least one of a cobalt element, a nickel element and a manganese element and further contain a lithium element and an oxygen element. Solid oxide-based electrolyte coats all or part of a surface of each of the active material particles. The solid sulfide-based electrolyte still coats 76.0% or more of a surface of each of the composite particles.
[039] An existing method of coating a surface of each of the particles containing active material with a solid sulfide-based electrolyte can be, for example, a gas-phase method such as pulsed laser deposition (hereafter, it can be referred to as PLD). However, PLD generally has a low deposition rate, so productivity is remarkably low. So it's not practical. In PLDt a target of a solid sulfide-based electrolyte is plasmolyzed by laser irradiation. At this time, there is a concern that the composition of the sulfide-based solid electrolyte changes and the solid state composition is not maintained. Another method of coating the surface of each of the particles containing active material with solid sulfide-based electrolyte can be, for example, a handcrafted method that uses a support, such as a planetary ball mill. However, in such a handcrafted method that uses a support, mechanical damage is applied by a collision with the support, with the result that the surface of each of the particles containing active material may be damaged. So, in order to avoid such mechanical damage, a craft method that does not use a support is desired.
[040] The inventors have repeatedly conducted research in a condition to improve a coating without changing the composition of a solid sulfide-based electrolyte when additionally coating each of the composite particles, wherein the surface of each active material particle is coated with a oxide-based solid electrolyte with sulfide-based solid electrolyte. The inventors diligently made an effort and, as a result, found that an active compound material having a greater coverage than that of an existing active material compound is obtained by adjusting the temperature of a mixture of compound particles and a sulfide-based solid electrolyte, and an energy in mixing time within certain specific variations in the coating time of each of the compound particles with the sulfide-based solid electrolyte. The inventors found that the reaction resistance of a lithium secondary battery using the active compound material so obtained depends on the sulfide-based solid electrolyte coating on the surface of each compound particle and the active compound material having a specific variation of the coating is capable of reducing the reaction resistance over time when used in a secondary lithium battery as compared to an existing active compound material, and when the invention is completed,
[041] The active material composite according to the invention includes the composite particles that serve as nuclei and a solid sulfide-based electrolyte that coats the surface of each of the composite particles. From now on, these particles of solid sulfide-based compounds and electrolytes will be described in sequence, 1.1 Compound Particles
[042] The composite particles according to the invention include particles of active material and an oxide-based solid electrolyte coating all or part of a surface of each of the active material particles. The active material particles according to the invention are composite particles that contain any one of a cobalt element (Co), a nickel element (Ni) and a manganese element (Mn), and which further contain a lithium element (Li) and an oxygen element (O). The active material particles are not specifically limited since the active material particles work as an active electrode material and specifically the active material particles are capable of occluding and/or emitting ions such as lithium ions. The active material particles according to the invention can be, for example, an express form following the formula of composition (A).LimNivx-yCOxMnyMjOμ (A)
[043](In the composition formula described above (A), M denotes at least one element selected from the group consisting of a phosphorus element (P), a titanium element (Ti), a tungsten element (W). zirconium (Zr) and an aluminum element (Al), m denotes a real number that satisfies 0 < m < 2, x and y denote real numbers that respectively satisfy 0Sxá1e0Syá1,z denotes a real number that satisfies 0 < z < 2, and n denotes one real number that satisfies 0 < n < 4.)
[044] The active material particles according to the invention can be, specifically, LiCoOz, LiNiOs, LiMn2O4, LiCoMnO4, LisNíMnsOs, LiNii/3Coi/3O2, LiNiPO4, UMnPO4, or U2NITIO4. Among these active material particles, in particular, LiNi1/3Co1/3IVIn1/3O2 is desirably used.
[045]Carbon particles, such as natural graphite particles, can also be used as active material particles according to the invention.
[046]The active material particles according to the invention can be nanocrystal particles of an active material or can be particles of polycrystal material! active in which a plurality of single crystals of active material are bonded at the level of the crystal face.
[047]The average particle diameter of the active material particles according to the invention is not specifically limited as long as the average particle diameter is smaller than the average particle diameter of the strained active compound material. The average particle diameter of the active material particles is desirably 0.1 to 30 µm. When each of the active material particles is a polycrystal active material particle in which a plurality of active material crystals are bound, the average particle diameter of the active material particles means the average particle diameter of the polycrystal active material particles. The average particle diameter of the particles according to the invention is calculated by an ordinary method. An example of a method of calculating the average particle diameter of particles is as follows. Initially, the particle diameter of a certain particle is calculated on the assumption that a certain particle is spherical in a transmission electron microscope image (hereinafter, referred to as TEM) or scanning electron microscope image (hereinafter referred to as , referred to as SEM) at an appropriate increase (for example, an increase from 50,000 to 1,000,000). Such particle diameter calculation by TEM observation or SEM observation is done on 200 to 300 particles of the same type, and the mean of these particles is determined as an average of the particle diameter,
[048) The oxide-based solid electrolyte according to the invention is not specifically limited as long as the oxide-based solid electrolyte contains an oxygen element (O) and has a chemoaffinity to the active material particles such that a degree as to be able to coat all or part of the surface of each of the active material particles, The solid oxide-based electrolyte according to the invention may be specifically LiNbO3, LiPON (lithium phosphorus oxynitrite), Lii ^AlojTh XPC^ h, La0.51Lio,34Tiθ2,g4l Li3PO4, Li2SíO2 or Li2S1O4. Among these solid oxide-based electrolytes, particularly, LiNbO3 is desirably used. A method of preparing the composite particles will be described in the chapter of “2. Active Material Composite Manufacturing Method" (described later),
[049]The thickness of the oxide-based solid electrolyte layer is desirably 1 nm to 100 nm. When the thickness of the oxide-based solid electrolyte layer is very large, the resistance can be large, so it is desirable that the oxide-based solid electrolyte layer thickness be as small as possible and the oxide-based solid electrolyte coating oxide on the surface of each active material particle is high. On the other hand, when the thickness of the oxide-based solid electrolyte layer is very small, there may be a portion of the surface of each active material particle, not coated with the oxide-based solid electrolyte layer, and, as a result, the active material particles come into contact with the sulfide-based solid electrolyte, and undergo degradation reaction. So the resistance can increase. The average thickness of the solid electrolyte layer (the oxide-based solid electrolyte layer and the sulfide-based solid electrolyte layer) is calculated by a common method. An example of a method of calculating the average thickness of the solid electrolyte layer is as follows. Initially, in a TEM image or SEM image of an appropriate magnification (eg, an increase of 50,000 to 1,000,000), the thickness of the solid electrolyte layer is measured at 5 to 10 points for a certain particle (a composite particle or a composite of active material). Such thickness measurement by TEM observation or SEM observation is made for 200 to 300 particles of the same type, and the average of all measured thicknesses of these particles is determined as the average thickness,
[050] In the invention, by interposing the oxide-based solid electrolyte between each active material particle and the sulfide-based solid electrolyte, it is possible to suppress the degradation reaction due to the contact between each active material particle and the sulfide-based solid electrolyte sulphide, 1-2. Sulfide-based Solid Electrolyte
[051] The solid sulfide-based electrolyte according to the invention still coats 76.0% or more of the surface of the composite particles described above. Here, 76.0% is a lower limit of the sulfide-based solid electrolyte coverage when the entire surface area of each compound particle is 100% (hereinafter, it may be referred to as the sulfide-based solid electrolyte coverage. ). When the coverage of the sulfide-based solid electrolyte is less than 76.0%, an active material compound, as in the case of an active material compound according to Comparative Example 1 (described later), exhibits a high reaction resistance when used on a battery. The coverage of the sulfide-based solid electrolyte is desirably greater than or equal to 85% and less than or equal to 95%, and is more desirably greater than or equal to 87% and less than or equal to 93%. When the coverage of the sulfide-based solid electrolyte exceeds 95%, it is assumed that a contact is likely between an electrically conductive aid, which is an electrode material, and each particle of active material decreases and a conductive electron pathway is interrupted in the case where the active compound material is, for example, mixed in one of the electrodes of a battery. So, there is a concern that the active material compound exhibits a high reaction resistance when used in a battery. When the coverage of the solid sulfide-based electrolyte is less than 85%, the surface of each composite particle is not sufficiently coated with the solid sulfide-based electrolyte. Thus, when the active material compound is used in a battery, a tonic conductive pathway is not sufficiently formed by the solid sulfide-based electrolyte, with the result that there is a concern that the active material compound exhibits a high reaction resistance. The coverage of the sulfide-based solid electrolyte is allowed to be calculated by a known method. A method of calculating sulfide-based solid electrolyte coverage can be, for example, a method of measuring the active material compound by X-ray photoelectronic spectroscopy (XPS), calculating an element ratio (ER) from the cross-sectional areas of the peak of the elements, and then calculating the coverage by using the following mathematical expression (B) on the basis of the element ratio (ER).
[052] Sulfide Based Solid Electrolyte Cover ~ ∑ERs/( ∑ERA+ ∑ER0+ ∑ERS) (B)
[053] (In the mathematical expression above (B), ∑ER$ denotes the sum total of the element proportions of the elements that make up the sulfide-based solid electrolyte and which are measurable by XPS, IERA denotes the sum total of the element proportions of the elements that make up the active material particles and that are measurable by XPS, and ∑ERo denotes the sum total of the element proportions of the elements that make up the oxide-based solid electrolyte and that are measured by XPS).
[054] The coverage of the sulfide-based solid electrolyte according to the invention is allowed to be qualitatively determined by SEM, or the like. For example, an electronic SEM reflection image for the surface of each compound particle indicates that a difference in element distribution is small on the surface as the contrast reduces, and it is found that the surface of each compound particle it is evenly coated with solid sulfide-based electrolyte in a high coverage. Particularly, in the case of the active material compound where the surface of each compound particle is coated with sulfide-based solid electrolyte particles, it appears that, in a secondary SEM electronic image for the surface of each compound particle, such as the unevenness reduces, grain boundaries of the sulfide-based solid electrolyte particles disappear and the surface of each compound particle is evenly coated with the sulfide-based solid electrolyte. A measure of the condition for a reflex electronic image and SEM secondary electronic image it can be, for example, a condition whose measurement is performed at an increase of 1,000 to 50,000 under the conditions of an accelerating voltage of 0.5 to 5 kV and an emission current of 1 to 100 μA using SEM ( produced by Hitachi High-technologies Corporation, product number SU8030), or the like.
[055] The sulfide-based solid electrolyte according to the invention is not specifically limited as long as the sulfide-based solid electrolyte contains a sulfur element (S) and has a chemoaffinity to the composite particles (particularly, oxide-based solid electrolyte ) to such a degree as to be able to coat the surface of each of the compounds particles described above. The solid sulfide-based electrolyte according to the invention can be specifically, Li2S-P2S6) Li2S-PzSs, Li2S-P2S3-P2S5, LizS-SiSa, LiaS-SizS, Li2S-B3S3, LigS-GeSs, Li2S-P2S "UI, I^S^Sfi-LhOLil, UMizS-SiSz-PaSs, IJ2S-SIS2-Li4SiO4, Li2S-SiS2' L3PO4, Li3PS4'L14GeS4T L13.4P0 6Si0.4S4, L_i3.25Px.75Geo. ^, Among these solid sulfide-based electrolytes, particularly, the solid sulfide-based electrolyte that contains Li2S“P2S5 in this composition is desirable, and LiaS-PzSδ-Li2O“Lil is more desirable.
[056] The ratio of the average thickness of the sulfide-based solid electrolyte layer to the average particle diameter of the composite particles is desirably (Average Particle Diameter of the Composite Particles):(Average Thickness of the Solid Electrolyte Layer based on Sulfide) = 30:1 to 95:1. When the sulfide-based solid electrolyte layer is too thick the average particle diameter of the composite particles, an electrical conduction aid, which is an electrode material, becomes hardened to the contact of the active material particles in the case where the composite material active is > for example, mixed into an electrode of a battery, and an electronic conduction pathway is interrupted, with the result that resistance may increase. On the other hand, when the oxide-based solid electrolyte layer is too thin for the average particle diameter of the composite particles, an ion pass, such as a lithium ion pass, may be interrupted, and resistance may increase. In the invention, it is most desirable that (Average Composite Particle Particle Diameter):(Average Thickness of Sulfide-based Solid Electrolyte Layer) = 38:1 to 63:1.
[057]Although depending on the purpose of the order, the average particle diameter of the active material compound according to the invention can be, for example, 0.1 to 35 µm.
[058] FIG. 1A to FIG. 1D are schematic cross-sectional views of active material compounds according to embodiments of the invention. FIG. 1A to FIG. 1D are views to qualitatively illustrate only one way in which each material is coated according to the modalities, and it is not always views that quantitatively reflect the coverage and particle diameter of each current solid electrolyte, the thickness of each electrolyte layer solid, or the like. As shown in FIG. 1A to FIG. 1D, each of the active material composites 100a to 100d includes a composite particle 3 and a sulfide-based solid electrolyte 4. The composite particle 3 is formed such that all or part of the surface of the active material particle is coated with the solid-based electrolyte. in oxide 2. The solid sulfide-based electrolyte 4 still coats all or part of the surface of the composite particle 3. The dotted lines in FIG. 1A and FIG. 1D each indicate particle boundaries of single crystal particles in polycrystal active material particle 1. The solid line indicating a boundary between active material particle 1 and oxide-based solid electrolyte layer 2 indicates an outer periphery of the active material particle. polycrystal formed from these mutually bonded single crystal particles. FIG. 1A is a schematic cross-sectional view of active material composite 100a. The active material compound 100a contains the compound particle 3 and the sulfide-based solid electrolyte 4. The compound particle 3 is formed by coating the entire surface of the active material particle 1 with the oxide-based solid electrolyte 2. The solid electrolyte sulfide-based 4 still coats the entire surface of the composite particle 3. FIG. 1B is a schematic cross-sectional view of active material composite 100b. The active material compound 100b contains the compound particle 3 and the sulfide-based solid electrolyte 4. The compound particle 3 is formed by coating part of the surface of the active material particle 1 with the oxide-based solid electrolyte 2. The solid electrolyte sulfide-based 4 still coats the entire surface of the compound particle 3. The coverage of the sulfide-based solid electrolyte in each of the active material compounds 100a, 100b is 100%. On the other hand, FIG, 1C is a cross-sectional view! schematic of active material compound 100c, active material compound 100c contains compound particle 3 and sulfide-based solid electrolyte 4, compound particle 3 is formed by coating the entire surface of active material particle 1 with solid electrolyte oxide-based 2. The sulfide-based solid electrolyte 4 still coats part of the surface of the composite particle 3. FIG. 1D is a schematic cross-sectional view of active material composite 100d. The active material composite 100d contains the composite particle 3 and the sulfide-based solid electrolyte 4. The composite particle 3 is formed by coating part of the surface of the active material particle 1 with the oxide-based solid electrolyte 2. The sulfide-based solid electrolyte 4 still coats part of the surface of the composite particle 3. The sulfide-based solid electrolyte coverage on each of the active material compounds 100c, 100d is greater than or equal to 76.0%, The active material compound according to the invention includes all active material compounds described above 100a to 100d. When a certain amount of active material compound is produced in volume, the same batch may include any of the active material compounds 100a to 100d or the same batch may mixed include two or more of the active material compounds 100a to 100d, FIG, 3 shows a cross-sectional SEM image of an active material compound currently taken using a experiment.
[059] As described herein, in the active material compound according to the invention, by adjusting the sulfide-based solid electrolyte cover as necessary, it is possible to reduce the internal resistance of the battery using the active material compound with respect to the internal resistance of the existing battery, 2, Manufacturing Method for Active Material Composite
[060] A manufacturing method for the active material composite according to the invention includes: a step of preparing the preparation of composite particles containing active material particles and a solid oxide-based electrolyte, the active material particles containing at least any one of a cobalt element, a nickel element and a manganese element and further containing a lithium element and an oxygen element, the solid oxide-based electrolyte coating all or part of a surface of each of the active material particles; and a coating step of coating a surface of each of the composite particles with a solid sulphide-based electrolyte by mixing the composite particles with the solid sulphide-based electrolyte with application of an energy, wherein the solid sulphide-based electrolyte deforms plastically, while a temperature of a mixture of the composite particles and the solid sulfide-based electrolyte is set at 100°C or below.
[061] The invention includes: (1) the preparation step of preparing the composite particles; and (2) the coating step of coating the surface of the composite particles with the solid sulfide-based electrolyte. The invention is not always limited to the two steps described above only; the invention may, for example, include a pre-treatment step, or the like, as will be described later other than the two steps described above. From now on, the above described steps (1), (2) and another step will be sequentially described. 2-1, Preparation Step
[062] This step is a step of preparing the composite particles described above. Active material particles and solid oxide-based electrolyte, which are the materials of composite particles, are as described in the chapter of ”1-1. Composite Particle". In the invention, the composite particles may be commercially available or may be prepared as needed. A method of preparing the composite particles may be, for example, a preparation method that uses spray coating as described in JP 2010- 073539 A, a fluidized bed rotor coating method, a spray method, an soaking method, a method using a lyophilizer, or the like.
[063]Before a coating step, a pretreatment step of mixing at least one of the composite particles and the solid sulfide-based electrolyte with a compound having an alkyl group can be further provided. By carrying out such a pretreatment step, it is possible to cause the compound having an alkyl group to adhere to the surface of each compound particle and/or the surface of the solid sulfide-based electrolyte. FIG, 16 is a graph showing the correlation between solid sulfide-based electrolyte coverage on each of the active material compounds according to Example 1 to Example 14 and Comparative Example 1 (described below) and a kneading time in the step of coating. FIG, 16 shows an approximate data curve of the active material compounds according to Example 9 to Example 11 for which no pretreatment step is carried out and the active material compound according to Comparative Example 1 for which no coating step is performed (i.e. kneading time is 0 minutes). According to the approximate curve, the coverage of the solid sulfide-based electrolyte significantly increases immediately after the start of the kneading process (0 to 10 minutes after kneading starts, particularly 0 to 1 minute after kneading starts). Therefore, when no pre-treatment steps are carried out, it is significantly difficult to establish the fabrication of the active material compound in which the coverage of the solid sulfide-based electrolyte is relatively low, particularly, the coverage of the solid sulfide-based electrolyte is 80 to 90%. On the other hand, FIG. 16 also shows the approximate data curve of each of the active material compounds according to Example 1 to Example 8 for which the pre-treatment step is carried out and the active material compound according to Comparative Example 1 for the which no coating step is performed (ie kneading time is 0 minutes). According to the approximate curve, the coverage of the solid sulfide-based electrolyte relatively increases gently with kneading time. Then when the pre-treatment step is carried out, it is possible to establish the fabrication of the active material compound having a desired coverage from the solid sulfide-based electrolyte, i.e., from the active material compound having a relatively low coverage, particularly, a coverage of 80 to 90%, for the active material compound having a relatively high coverage. -treatment in this form is presumably that a free surface energy decreases due to modification of the surfaces of the sulfide-based solid electrolyte and particles composed of the alkyl group, with the result that the energy becomes hard to apply to the sulfide-based solid electrolyte, and then the solid sulfide-based electrolyte becomes hard to coat the composite particles.
[064] The compound having an alkyl group that is used in the pretreatment step is not specifically limited as long as a compound containing an alkyl group that decreases adhesion at the interfaces of the composite particles and/or the solid sulfide-based electrolyte, i.e., an alkyl group-containing compound that reduces the free surface energy in these materials. An example of the compound having an alkyl group may be an alkylamine, such as trimethylamine ((CH3)3N), triethylamine (C2H5)3N), tripropylamine (C3H7)3N) and tributylamine (C4H$)3N); and ether compound, such as ethyl ether ((C2H5)2O), propyl ether ((C3H7)2O) and butyl ether ((C4H9)Z)O); a nitrile compound such as butyl nitrile (C4H9CN), pentyl nitrile (C5H11CN) and isopropyl nitrile (i-CsHyCN); an ester compound such as butyl acetate (C2H5CO2C4Hg), butyl butyrate (C4HgCO2C4H3) and ethyl butyrate (C4H9CO2C2H5); an aromatic compound such as benzene (C6He), xylene (C8H10) and toluene (C7HS); or the like. Among these compounds, an alkylamine is most desirably used in the pretreatment step.
[065] One method of mixing in the pretreatment step is more desirably wet mixing that uses a dispersion medium in terms of uniformly causing the compound having an alkyl group to adhere to the surface of each compound particle and/or the surface of the electrolyte sulfide-based solid. An example of the dispersion medium that can be used in the wet mixture may be an alkane, such as mhexane (C6Hi4)t n-heptane (C7Hw) and n-octane (CδHi8); an ether compound such as ethyl ether propyl ether (C3H7)2O) and butyl ether ((C^hO); a nitrile compound such as butyl nitrile (C4H9CN), pentyl nitrile and isopropyl nitrile (i-C3H7CN); ester such as butyl acetate (C2H5CO2C4H9), butyl butyrate (C4H9CO2C4H9) and ethyl butyrate (C4H9CO2C2H5); an aromatic compound such as benzene (CβH^), xylene (CgHw) and toluene (C7He); or the like; These dispersing means can be used alone or can be used in combination of two or more thereof.When wet mixing is made, a mixture after wet mixing can be dried by properly heating the mixture to remove the dispersing medium.
[066]Hereinafter, an example of a pre-treatment step will be described. First, the composite particles, the solid sulfide-based electrolyte. The compound having an alkyl group and the appropriate dispersion medium are mixed. At this time, materials can be highly dispersed in the dispersion medium by ultrasonic irradiation for mixing. Subsequently, the obtained mixture is heated under the condition of temperature of 80 to 120° C for 1 to 5 hours to dry. The dry mix is used in the next coating step. 2-2. Coating Step
[067] This step is a step of coating the surface of each of the composite particles with the solid sulfide-based electrolyte by mixing the composite particles with the solid sulfide-based electrolyte with application of an energy, in which the electrolyte sulfide-based solid plastically deforms while the temperature of the mixture is adjusted to 100°C or below. The sulfide-based solid electrolyte that is used in this step is as described in the chapter of "1- 2. Sulfide-Based Solid Electrolyte1*.
[068] In this step, sulfide-based solid electrolyte particles having an average particle diameter of 1 µm or smaller are desirably used as the sulfide-based solid electrolyte. As shown in Table 1 (described later), in the active material compounds according to Example 12 and Example 13, manufactured by using sulfide-based solid electrolyte particles having an average particle diameter of 1 µm or less, the coating of the sulfide-based solid electrolyte is greater than 4% or more than that of each of the active material compounds for Example 10 and Example 11, manufactured by using the sulfide-based solid electrolyte particles having an average particle diameter greater than 1 µm . This is presumably because, as the average particle diameter of the sulfide-based solid electrolyte particles reduces, the surface of each of the composite particles is easily completely coated with the sulfide-based solid electrolyte particles without any gaps. In this way, it is possible to further improve the coverage of solid sulfide-based electrolyte by using solid sulfide-based electrolyte having a smaller mean particle diameter, with the result that it is possible to suppress the reaction resistance of a secondary lithium battery that uses the above active material compound to a lesser degree. An example that exhibits such a significantly high coverage by directly utilizing small particles of the sulfide-based solid electrolyte by coating other particles is not known in the existing art. The average particle diameter of the sulfide-based solid electrolyte particles which are used in the invention is more desirably less than or equal to 0.9 µm and still desirably less than or equal to 0.8 µm. The average particle diameter is desirably greater than or equal to 0.01 µm.
[069] An additive amount of the sulfide-based solid electrolyte to the composite particles is desirably an additive amount such as the average thickness of the sulfide-based solid electrolyte layer, described in the chapter of 1.1-2. Sulfide-based Solid Electrolyte” is obtained. Specifically, it is desirable to add 5 to 25 parts by mass of the solid sulfide-based electrolyte to the 100 parts by mass of the composite particles, and it is more desirable to add 8 to 22 parts by mass of the solid sulfide-based electrolyte to the 100 parts by mass of the composite particles.
[070]In this step, the composite particles and the solid sulfide-based electrolyte are mixed while the temperature of the mixture is adjusted to 100°C or below. When the temperature of the mixture exceeds 100°C, the solid sulfide-based electrolyte changes due to heating, thus active material composite is not obtained. By suppressing the mixing temperature to 100°C or below, it is possible to avoid thermal damage at manufacturing time and to manufacture active material composite where the sulfide-based solid electrolyte coverage on composite particle surfaces is higher than or equal to to 76.0%. The temperature of the mixture in the coating step is desirably less than or equal to 90°C and more desirably less than or equal to 80°C.
[071] In this step, the composite particles and the solid sulfide-based electrolyte are mixed with application of an energy in which the solid sulfide-based electrolyte plastically deforms. Plastic deformation of the solid sulfide-based electrolyte in the invention is that the solid sulfide-based electrolyte does not retain its original shape in the early stage of the coating step and is irreversibly fluidized. At this time, chemical bonds between atoms that make up the solid sulfide-based electrolyte are not cleaved or the composition of the solid sulfide-based electrolyte is not changed. Particularly, when particles of the solid sulfide-based electrolyte are used as a raw material, deformation The plastic in the invention is that the shape of each of the sulfide-based solid electrolyte particles collapse and, as a result, any sulfide-based solid electrolyte particles mix with each other and all or parts of the grain boundaries between the particles disappear .
[072] An example of energy in which the solid sulfide-based electrolyte plastically deforms may be an energy that is applied to the solid sulfide-based electrolyte such that the solid sulfide-based electrolyte produces a fracture energy that is applied to the sulfide-based solid electrolyte to a fracture of sulfide-based solid electrolyte, a current of (physical) energy that is stored in the sulfide-based solid electrolyte to form sulfide-based solid electrolyte currents, or the like. From now on, the energy at which the solid sulfide-based electrolyte plastically deforms will still be described in terms of yield. An example of energy in which the solid sulfide-based electrolyte plastically deforms might be an energy in which the stress reaches a higher yield point during yield when the so-called stress current diagram is plotted where the ordinate axis represents stress o (N/mm*) and the abscissa axis represents current (%). An example of an energy in which the solid sulfide-based electrolyte plastically deforms in the stress current diagram where superior efficiency is not clearly recognized might be an energy in which the stress test (ie, stress in time when a current plastic left after discharging is 0.2%) is applied to solid sulfide-based electrolyte. The stress current diagram of solid sulfide-based electrolyte is obtained by a method according to JISK7181, particularly by plotting "10.1 Compressive Stress" and "10.2 Compressive Current" at least measured according to "9 Procedure" of the standard with the use of "5 Device" and "6 Specimen" of the pattern.
[073] In the coating step, it is desirable to add a shear force to the mixture of the composite particles and the solid sulfide-based electrolyte in order to apply the plastically deforming energy described above. An example of a method of adding shear force in order to apply plastically deforming energy might be a mechanical kneading method that applies frictional shear energy to the mixture in a dry system between a rotating rotor and a surface of Wall. An example of a device that is capable of achieving such a mechanical kneading method might be a dry kneading machine that does not use a medium. The dry kneading machine that can be used in the invention is not specifically limited since the drying kneading machine is generally used, and can be, for example, Nobilta (product name, produced by Hosokawa Micron Corporation), mechanofusion, hi “ bridization, COMPOSI (product name, produced by Nippon Coke & Engineering Company, Limited) or the like. By employing such dry kneading machines that do not use a medium, it is possible to reduce mechanical damage to the active material particles and compared to the case where a kneading machine that uses a medium, such as a planetary ball mill, is used. A specific condition under which plastically deforming energy is applied using the dry kneading machine can be, for example, a condition that the blade-to-wall space is 0.1 to 8 mm and the rotation speed is 500 at 5,000 rpm. The dry kneading machine is generally used for the purposes of mixing relatively hard materials with each other. In the invention, solid sulfide-based electrolyte which is a relatively light material is used, so that it is possible to apply sufficient energy to plastically deform the solid sulfide-based electrolyte even at a relatively low rotation speed in the dry kneading machine.
[074] In the coating step, it is desirable that the solid sulfide-based electrolyte is further added to a mixture after mixing for 10 minutes or greater and be mixed with application of an energy, in which the solid sulfide-based electrolyte plastically deforms, while the temperature of the mixture is adjusted to 100°C or below. By mixing adds! of the solid sulfide-based electrolyte in the coating step in this form, an active material compound having a significantly high coverage of the sulfide-based solid electrolyte in the compound particles as shown in Example 14 (described later) is obtained. FIG. 17 is a graph showing the correlation between the sulfide-based solid electrolyte coverage in each of the active material compounds according to Example 4, and the like, and the reaction resistance of each lithium secondary battery using those compounds of active materials. According to FIG. 17, it appears that the secondary lithium battery reaction resistance is minimal in the case where the sulfide-based solid electrolyte coverage is 93%. However, when the type or amount of additive other than Example 4, and the like, is employed for another electrode material, such as an electrically conductive material, the sulfide-based solid electrolyte coating where the secondary lithium battery resistance is the lower can change to a point higher than 93%. In such a case too, by employing a method of further mixing the sulfide-based solid electrolyte in the coating step, it is possible to improve the coverage of the solid sulfide-based electrolyte. sulfide and suppress the reaction resistance of the secondary lithium battery which uses the active material compound to a lesser degree. The number of times the solid sulfide-based electrolyte is added to the mixture is desirably 1 to 10 times and more desirably 1 to 5 times.
[075] From now on, an example where the coating step is performed after the pre-treatment step will be described as an example of the coating step. Initially, precursor powder after being subjected to the pretreatment step is placed in the dry kneading machine. Subsequently, the active material compound according to the invention is obtained by carrying out the kneading process for 30 seconds to 3 hours under the condition that the blade-to-wall space is 0.1 to 8 mm and the rotation speed is 500 to 5.00 rpm while mixing temperature is adjusted to 100°C or below.
[076] Hereinafter, an example where the coating step is carried out without carrying out the pretreatment step will be described as an example of the coating step. Initially, the composite particles and solid sulfide-based electrolyte are placed in the dry kneading machine. Subsequently, the active material compound according to the invention is obtained by carrying out the kneading process for 30 seconds to 3 hours under the condition that the blade-to-wall space is 0.1 to 8 mm and the speed of rotation is 500 to 5,000 rpm while the temperature of the mixture is set at 100°C or below. A dry synthesis that does not include the pretreatment step in this form does not require a dispersion medium or the like, so it is advantageous that the cost is reduced.
[077] From now on, an example where the solid sulfide-based electrolyte is further mixed in the coating step will be described as an example of the coating step. Initially, the composite particles and part of the solid sulfide-based electrolyte are placed in the dry mechanical kneader. Subsequently, kneading process is carried out for 30 seconds to 3 hours under the condition that the blade-to-wall space is 0.1 to 8 mm and the rotation speed is 500 to 5,000 rpm while the mixing temperature is adjusted to 100° C or below. Subsequently, the other part of the solid sulfide-based electrolyte is placed in the dry mechanical kneader, and the process is carried out under the condition described above. In this form, the active material compound according to the invention is obtained by alternatively carrying out the addition of the solid sulfide-based electrolyte and the kneading process.
[078]With the manufacturing method according to the invention, it is possible to plastically de-form the solid sulfide-based electrolyte without causing thermal damage to the solid sulfide-based electrolyte. Thus, it is possible to manufacture the active material composite having a greater coverage of the solid sulfide-based electrolyte in the composite particles than that of the active material composite which is manufactured according to the existing technique. 3. Secondary Lithium Battery
[079]The lithium secondary battery according to the invention is a lithium secondary battery that includes a positive electrode, a negative electrode and an electrolyte layer interposed between the positive electrode and the negative electrode. At least one positive electrode and the negative electrode contain at least one of the active material compound described above and the active compound material manufactured according to the methods described above, because the secondary lithium battery according to the invention contains the active material compound described above in which 76.0% or more of the surface of each of the composite particles is coated with the solid sulfide-based electrolyte, the secondary lithium battery is able to suppress the reaction resistance to a lesser degree as compared to the existing secondary lithium battery. The reaction resistance of the secondary lithium battery according to the invention can be, for example, obtained from a circular arc component in the Nyquist diagram obtained using the high-frequency impedance method,
[080] FIG. 2 is a view showing an example of the configuration of the secondary lithium battery layer according to the invention and is a view schematically showing a transverse taken in a laminated direction. The secondary lithium battery according to the invention is not always limited to this example only. The secondary lithium battery 200 includes a positive electrode 16, a negative electrode 17 and the electrolyte layer 11.0 positive electrode 16 includes an active material layer of the positive electrode 12 and a current collector from positive electrode 14. The negative electrode 17 includes a active material layer of negative electrode 13 and a current collector on negative electrode 15. Electrolyte layer 11 is maintained between positive electrode 16 and negative electrode 17. From now on, positive electrode, negative electrode and layer of electrolyte which are used in the secondary lithium battery according to the invention and a separator and a battery box which are suitably used in the secondary lithium battery according to the invention will be described in detail.
[081] The positive electrode that is used in the invention desirably includes the active material layer on the positive electrode that contains the active compound material described above, and generally still includes collecting current from the positive electrode and a positive electrode conductor connected to the collector. current of the positive electrode.
[082]The active material of the positive electrode can be only the active material composite described above according to the invention alone or in combination of the active material composite and another one or two or more active materials in the positive electrode. An example of the active material of the positive electrode can be specifically UCoO2, LiNh/sCovsOa, LiNIPO4, LiMnPO4, LiNiO2, LiMn2O4t UOoMnO4, Li2NiMn3O8, Li3Fe2(PO4)3, Li3V2(PO4)3, or the like. The surfaces of fine particles made of active material on the positive electrode can be coated with LiNbOs, or the like. The surfaces of fine particles made from the active material of the positive electrode can be coated with UNbO3 or the like. The total active material content of the positive electrode in the active material layer of the positive electrode generally falls within the range of 50 to 90 percent© by weight.
[083] Although the thickness of the active material layer of the positive electrode that is used in the invention varies with, for example, the purpose of the intended application of the secondary lithium battery, the thickness of the active material layer of the positive electrode is desirably within the 10 to 250 µm range, most desirably is within the 20 to 20 µm range, and particularly matte desirably is within the 30 to 150 µm range,
[084]The active material layer of the positive electrode may contain an electrically conductive material, a connector, or the like, where necessary. The electrically conductive material that is used in the invention is not specifically limited since the electrically conductive material is capable of improving the electrical conductivity of the active material layer of the positive electrode, and may be, for example, carbon black, such as acetylene black and Black Ketjen. The content of the electrically conductive material in the active material layer of the positive electrode varies with the type of electrically conductive material, and is generally within the range of 1 to 30 percent by weight,
[085] An example of a binder that is used in the invention may be polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), or the like. The binder content in the active material layer of the positive electrode must be in an amount by which the active material of the positive electrode, and the like, is fixed, and is desirably greater. The content of the binder is generally within the range of 1 to 10 percent by weight. A dispersion medium such as N-methyl-2-pyrrolidone and acetone can be used to prepare the positive electrode active material,
[086] The positive electrode current collector that is used in the invention has the function of collecting current in the active material layer of the positive electrode. An example of the positive electrode current collector material can be aluminum, SUS, nickel, iron , titanium or the like. Among these, the positive electrode current collector material described above is desirably aluminum or SUS. An example of the shape of the current collector of the positive electrode may be a blade shape, a sheet shape, a net shape or the like. Among others, the shape of the current collector of the positive electrode is desirably a blade shape.
[087]A positive electrode fabrication method that is used in the invention is not specifically limited as long as it is possible to obtain the positive electrode described above. After the active material layer of the positive electrode is formed, the active material layer of the positive electrode can be pressed in order to improve the electrode density,
[088) The negative electrode that is used in the invention desirably includes the negative electrode active material layer that contains the active material compound described above, and generally further includes the negative electrode current collector and a negative electrode conductor connected to the negative electrode current collector.
[089]The active material of the negative electrode can be only the active material compound described above according to the invention alone or in combination of the active material compound and another one or two active materials of the negative electrode. Other negative electrode active material is not specifically limited as long as the negative electrode active material is capable of occluding and/or emitting lithium ions. An example of another active material of the negative electrode might be a lithium metal, a lithium alloy, an oxide metal that contains a lithium element, a metal sulfide that contains a lithium element, a meta! nitride containing a lithium element, a carbon material such as graphite, or the like. The active material of the negative electrode can be in a powder form or it can be in a thin film form. An example of a lithium alloy may be a lithium aluminum alloy, a lithium tin alloy, a lithium lead alloy, a lithium silicon alloy or the like. An example of the metal oxide containing a lithium element may be a lithium titanium oxide, or the like. An example of a metal nitrite containing a lithium element may be a lithium cobalt nitride, a lithium iron nitride, a lithium manganese nitride, or the like. The active material of the negative electrode can also be lithium coated with a solid electrolyte.
[090]The negative electrode active material layer described above contains only the negative electrode material or may contain at least one of an electrically conductive material and a connector in addition to the negative electrode active material. For example, when the active material of the negative electrode is in a blade shape, the active material layer of the negative electrode can be formed to contain only the active material of the negative electrode. On the other hand, when the active material of the negative electrode is in a powder form, the active material layer of the negative electrode can be formed to include the active material of the negative electrode and the connector. The electrically conductive material and the connector are respectively similar to the electrically conductive material and the connector contained in the active material layer of the positive electrode described above, so its description is omitted here. The film thickness of the active material layer of the negative electrode is not specifically limited. For example, the film thickness is desirably within the range of 10 to 100 µm, and more desirably is within the range of 10 to 50 µm,
[091 ]The electrode active material layer of at least one positive electrode described above and the negative electrode described above can be configured to contain at least one active material in the electrode and one electrolyte in the electrode. In this case, the electrode electrolyte may be a solid electrolyte, such as a solid oxide electrolyte and a solid sulfide electrolyte (described later), a gel electrolyte, or the like,
[092] The negative electrode current collector material may be similar to the positive electrode current collector material described above. A similar form of the positive electrode current collector form described above can be employed as the current collector form of the negative electrode.
[093]A method of fabricating the negative electrode that is used in the invention is not specifically limited since the negative electrode described above is obtained by the method. After the active material layer of the negative electrode is formed, the active material layer of the negative electrode can be pressed in order to improve the electrode density.
[094J The electrode layer that is used in the invention is kept between the positive electrode and the negative electrode, and has the function of exchanging lithium ions between the positive electrode and the negative electrode. The electrolyte layer can be an electrolyte solution , a gel electrolyte, a solid electrolyte, or the like. Only one of these can be used alone, or two or more of them can be used in combination.
[095]The electrolyte solution can be a non-aqueous electrolyte solution or an aqueous electrolyte solution. The non-aqueous electrolytic solution generally contains a lithium salt and a non-aqueous solvent. An example of the lithium salt described above might be a non-organic lithium salt such as LiPFS(LiBF4, LiCIO4 and LiAsF6; an organic lithium salt such as LiCF3SO3, LiN(SO2CF3)2(Li-TFSA), UN( SO2C2F5)2 and LiCfSOzCFah, or the like. An example of the non-aqueous solvent described above may be ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), ethyl carbonate, butylene carbonate, y-butyrolactone, sulfolane, acetonitrile (AcN), dimethyl methane, 1,2-dimethoxyethane (DME), 1,3-dimethoxypropane, diethyl ether, tetraethylene glycol dimethyl ether (TEGDME) ), tetrahydrofuran, 2-methyltetrahydrofuran, dimethyl sulfoxide (DMSO), a mixture thereof, or the like The concentration of the lithium salt in the non-aqueous electrolytic solution is, for example, 0.5 to 3 mol/kg.
[096] In the invention, an example of the non-aqueous electrolytic solution or the non-aqueous solvent may be an ionic liquid, or the like. An example of an ionic liquid may be N-methyl-N-propyl pyrrolidinium bis(trifluoromethanesulfonyl)amide (PP13TFSA), N-methyl-N-propyl pyrrolidinium bis(trifluoromethanesulfonyl)amide (P13TFSA), N-butyl bis(trifluoromethanesulfonyl)amide -N-methyl pyrrolidinium (P14TFSA), N,N-diethyl"N-methikN" bis(trifluoromethanesulfonyl)amide(2-methoxyethyl)ammonium (DEMETFSA), N,N,N"tnmethyl-N bis(trifluoromethanesulfonyl)amide -propfI ammonium (TMPATFSA), or the like.
[097] The aqueous electrolytic solution usually contains a lithium salt and water. An example of a lithium salt may be a lithium salt such as LiOH, LiCl, LiNO3 and CH3CO2LI or the like,
[098] The gel electrolyte that is used in the invention is generally gelled by adding a polymer to a non-aqueous electrolyte solution. An example of a non-aqueous gel electrolyte is obtained by gelling the non-aqueous electrolyte solution described above by the addition of a polymer such as polyethylene oxide (PEO), polyacrylonitrile (PAN) polymethyl methacrylate (PMMA), polyurethane, polyacrylate and/or cellulose, for the non-aqueous electrolytic solution. In the invention, a non-aqueous gel electrolyte based on L!TFSA(LiN(CF3SO2)2)"PEO is desirable
[099] The solid electrolyte can be an oxide-based solid electrolyte, a sulfide-based solid electrolyte, a polymer electrolyte, or the like. Of these solid electrolytes, a specific example of the oxide-based solid electrolyte is the one as described in the chapter of "1-1, Compound Particles", and a specific example of the sulfide-based solid electrolyte is the one as described in the chapter of "1- two. Sulfide-based Solid Electrolyte. The polymer electrolyte usually contains a lithium salt and a polymer. The lithium salt can be at least one of the non-organic lithium salts described above and organic lithium salts. The polymer is not specifically limited since that the polymer forms a complex with the lithium salt, and may be, for example, polyethylene oxide, or the like,
[0100] The secondary lithium battery according to the invention may include a separator, impregnated with an electrolytic solution, between the positive electrode and the negative electrode. An example of the separator described above may be a porous film such as polyethylene and polypropylene; a non-woven fabric, such as a resin non-woven fabric and a fiberglass non-woven fabric, or the like.
[0101] The lithium secondary battery according to the invention generally includes a battery box that accommodates the above-described positive electrode, negative electrode, electrolyte layer, and the like. The shape of the battery box can specifically have a coin shape, a flat plate shape, a cylindrical shape, a laminated shape or the like.
[0102] From now on, the invention will be further specifically described by way of examples; however, the invention is not limited to examples only. 1. Manufacturing of Active Material Composite Example 1
[0103] Initially, composite particles in which LiNii^CovsMnvs particles (active material particles) are coated with LiNbO3 (solid oxide-based electrolyte) were prepared (preparation step). The average particle diameter of the composite particles was 4.5 µm. Subsequently, 50 g of the composite particles, 10.8 g of 48.5Li2S-17.5P2S5-4Lí2O-30L!l particles (sulfide-based solid electrolyte, mean particle diameter: 1.5 µm), 9 g of tributylamine (( C4H9)3N) which is a compound having an alkyl group, and 75 g of heptane (CyHie) which is a dispersion medium were mixed in a wet state, and further subjected to ultrasonic dispersion. A mixture after ultrasonic dispersion was heated for 2 hours under the temperature condition of 100°C, and precursor powder was obtained (pretreatment step). Subsequently, the precursor powder was placed in the dry mechanical kneader (produced by Hosokawa Micron Corporation, product name: NOB-MINI), and was subjected to the kneading process for 1 minute under the condition that the blade-to-wall space is 1 mm and the rotation speed is 3000 rpm while the temperature of the mixture was adjusted to 50°C (coating step). Then, the active material compound according to Example 1 was manufactured. Example 2
[0104] The active material compound according to Example 2 was manufactured as in the case of Example 1 except that the kneading time in the re-coating step was changed from 1 minute to 2 minutes in Example 1. Example 3
[0105] The active material compound according to Example 3 was manufactured as in the case of Example 1 except that the kneading time in the coating step was changed from 1 minute to 4 minutes in Example 1, Example 4
[0106] The active material compound according to Example 4 was manufactured as in the case of Example 1 except that the kneading time in the coating step was changed from 1 minute to 8 minutes in Example 1. Example 5
[0107] The active material compound according to Example 5 was manufactured as in the case of Example 1 except that the kneading time in the coating step was changed from 1 minute to 12 minutes in Example 1, Example 6
[0108] The active material compound according to Example 6 was manufactured as in the case of Example 1 except that the kneading time in the coating step was changed from 1 minute to 16 minutes in Example t Example 7
[0109] The active material compound according to Example 7 was manufactured as in the case of Example 1 except that the kneading time in the coating step was changed from 1 minute to 20 minutes in Example 1. Example 8
[0110] The active material compound according to Example 8 was manufactured as in the case of Example 1 except that the kneading time in the coating step was changed from 1 minute to 30 minutes in Example 1. Example 9
[0111] Initially, composite particles in which Li-Ni1/3Cov3Mn1/3θ2 particles (active material particles) are coated with LiNbO$ (solid oxide-based electrolyte) were prepared (preparation step). The average particle diameter of the composite of particles was 4.5 µm. Subsequently, 50 g of the composite particles and 10.8 g of 48.5Li2S“17.5P2S5-4Li2O-30Lil particles (sulfide-based solid electrolyte, mean particle diameter: 1.5 μm) were placed in the dry kneading machine ( produced by Hosokawa Micron Corporation, product name: NOB-MINI), and were subjected to the kneading process for 10 minutes under the condition that the blade-to-wall space is 1mm and the rotation speed is 3,000 rpm while the temperature of the mixture was adjusted to 50°C (coating step). Then the active material compound according to Example 9 was manufactured. Example 10
[0112] The active material compound according to Example 10 was manufactured as in the case of Example 9 except that the kneading time in the coating step was changed from 10 minutes to 20 minutes in Example 9, Example 11
[0113] The active material compound according to Example 11 was manufactured as in the case of Example 9 except that the kneading time in the coating step was changed from 10 minutes to 30 minutes in Example 9, Example 12
[0114) The active material compound according to Example 12 was manufactured as in the case of Example 9 except that 10.8 g of particles 48.5Li2S-i7.5P2.S5-4Li2O-30Lil (average particle diameter: 0, 8 μm) were used instead of 10.8 g of 48.5Lí2S-17.5P;>Ss-4Li2O-30Lil particles (mean particle diameter: 1.5 μm) and the kneading time in the coating step was changed by 10 minute to 30 minutes in Example 9. Example 13
[0115] The active material compound according to Example 13 was manufactured as in the case of Example 9 except that 10.8 g of particles 48.5Li2S“17.5P2S5-4LfoO~30Líl (average particle diameter: 0.8 μm ) were used instead of 10.8g of 48t5Lí2S-17.5P2Sr4Li2O'30Lil particles (average particle diameter: 1.5 μm) and the kneading time in the coating step was changed from 10 minutes to 30 minutes in Example 9. Example 14
[0116] Initially, composite particles in which Li-Niv3Coi/3Mni/3O2 particles (active material particles) are coated with LiNbO3 (solid oxide-based electrolyte) were prepared (preparation step). The mean particle diameter of the composite particles was 4.5 µm. Subsequently, 50 g of the composite particles and 3.5 g of 48.5Li2S“17.5P2S5-4Li2O30Lil particles (sulfide-based solid electrolyte, mean particle diameter: 0.8 μm) were placed in the dry kneading machine (produced by Hosokawa Micron Corporation, product name: NOB-MINI), and were subjected to the kneading process for 10 minutes under the condition that the blade-to-wall space is 1mm and the rotation speed is 3,000 rpm while the mixing temperature was adjusted to 50°C ((first) coating step). Subsequently, 3.5 g of 48.5Lí2S“17.5P2S5-4Li2O'30UI particles (sulfide-based solid electrolyte, mean particle diameter: 0.8 μm) were further placed in the dry kneading machine after the (first) step of coating, and were subjected to the kneading process for 10 minutes under a condition similar to that of the (first) coating step ((second) coating step). Subsequently, 3.8 g of particles of 48.5Lí2S'17.5P2S5-4Lí2O“30Líl (sulfide-based solid electrolyte, mean particle diameter: 0.8 µm) were further placed in the dry kneading machine after the (second) coating step, and were subjected to the kneading process for 40 minutes under a condition similar to that of the (first) coating step ((third) coating step). Then, the active material compound was manufactured. Example 1 Reference
[0117]24 g of natural graphite particles (particles of active material, mean particle diameter: 20 μm) and 10.4 g of 48.5Lí2S-17.5P2S5" 4Li2O"30Lil particles (sulfide-based solid electrolyte, average particle diameter: 0.8 μm) were placed in the dry kneading machine (produced by Hosokawa Micron Corporation, product name: NOB-MINI), and were subjected to the kneading process for 60 minutes under the condition that the Sâmina space -to-wall is 1mm and the rotation speed is 3,000 rpm while the temperature of the mixture was adjusted to 50°C (coating step) Then, the active material compound according to Reference Example 1 was manufactured. Comparative Example 1
[0118] Initially, composite particles in which Li-Nh/sCovaMnj/sOs particles (active material particles) are coated with LiNbOg (oxide-based solid electrolyte) were prepared (preparation step), The average particle diameter of the composite particles was 4.5 µm. Subsequently, 50 g of the composite particles and 10.8 g of 48.5Li2S-rt7.5P2S5-4Lí2O-30Líl particles (sulfide-based solid electrolyte, mean particle diameter: 1.5 μm), 9 g of tributylamine ((CrfH) ^N) which is a compound having an alkyl group, and 75 g of heptane (CZHI6) which is a dispersion medium were mixed in a wet state, and further subjected to ultrasonic dispersion. Comparative Example 1 was manufactured That is, in Comparative Example 1, neither heating after the ultrasonic dispersion nor the coating step of the invention was carried out. 2. Observation of the Active Material Compound Morphology 2-1. Observation of Transverse Morphology by SEM
[0119]The active material compound according to Example 13 was subjected to transverse polishing (CP) treatment, and the transverse morphology of the active material compound was observed using SEM. The details of the measurement are as follows.
[0120]SEM: Produced by Hitachi Hig ^technologies Corporation, product number SU8030
[0121] Acceleration voltage: 1 kV
[0122] Emission current: 10 μA
[0123] Increase: 20,000
[0124] FIG 3 is an SEM cross-sectional image of the active material composite as per Example 13. As is apparent from FIG 3, within the active material composite as per Example 13, LiNiwCovsMnvsOs particles that are active material particles are bonded each other, and a particle of polycrystalline active material 21 is formed. As is apparent from FIG 3, the then-configured polycrystal active material particle 21 is coated with an oxide-based solid electrolyte layer 22 having an average thickness of 10 nm, and the surface of the oxide-based solid electrolyte layer 22 has been further coated. with a solid sulfide-based electrolyte layer 23 having an average thickness of 200 nm. In this case, it appears that the active material compound according to Example 13 includes oxide-based solid electrolyte layer and the sulfide-based solid electrolyte layer significantly thinner than the particle diameter of the active material compound. 2-2. Observation of Surface Morphology by SEM
[0125] The surface morphology of active material compounds according to Example 1 to Example 14, and Comparative Example 1 and the surface morphology of natural graphite according to Reference Example 1 were observed by SEM using samples in which active material compounds and natural graphite have been sprayed into a powder form. The morphology of each of the active material compounds was evaluated based on the corresponding secondary electronic image obtained, and a coated state of the sulfide-based solid electrolyte in each of the active material compounds was evaluated on the basis of a contrast difference in the corresponding reflex electronic image. A measurement condition for observing surface morphology is the same as the measurement condition for observing transverse morphology described above.
[0126] FIG 4 to FIG 15B and FIG 19A to FIG 20B are SEM surface images of active material compounds according to Example 1 to Example 4, Example 8 to Example 14 and Comparative Example 1 and the SEM surface image of the natural graphite according to Reference Example 1. In the figures, a secondary electronic image (figure suffixed A) and a corresponding electronic reflection image (figure suffixed B) are shown one above the other. Initially, active material compounds according to Example 1 to Example 4, Example 8 to Example 14 and Comparative Example 1, which use Li-NiwsCovaMnvaOa particles (active material particles) as a raw material, will be analyzed. From FIG. 19A, on the surface of the active material compound according to Comparative Example 1, the grain boundaries of the sulfide-based solid electrolyte particles are independently and clearly recognized. For this reason, it appears that, in the fabrication method according to Comparative Example 1, a sufficient energy at which the sulfite-based solid electrolyte particles plastically deform was not applied. In FIG. 19B, a bright colored portion (niobium element, and the like) and a dark colored portion (phosphor element, sulfur element, and the like) are clearly separated. For this reason, it appears that, in the active material compound according to Comparative Example 1, the solid oxide-based electrolyte containing a niobium element is not sufficiently coated with the solid sulfide-based electrolyte containing a phosphorus element, and the like, and solid oxide-based electrolyte is exposed to the surface of the active material compound. On the other hand, as is apparent from FIG. 4A to FIG. 14A, on the surface of each active material compound according to Example 1 to Example 4, and Example 8 to Example 14, the solid sulfide-based electrolyte particles are bonded together, and the boundaries of the grains are unclear. For that reason, it appears that, at least the manufacturing methods according to Examples 1 to Example 4, and Examples 8 to Examples 14, a sufficient energy to which the solid sulfide-based electrolyte particles plastically deform was applied. In FIG, 4B to FIG. 14B, a bright color portion (niobium element, and the like) and a dark color portion (phosphor element, sulfur element, and the like) have been mixed together, and an element distribution is more uniform than that of FIG. 19B. For this reason, it appears that, at least one active material compound according to Example 1 to Example 4, and Example 8 to Example 14, the solid oxide-based electrolyte containing a niobium element is sufficiently coated with the solid-based electrolyte in sulfide containing a phosphorus element, and the like.
[0127]Among these examples, when Example 1 to Example 4 and Example 8 (FIG. 4A to FIG, 8B) are particularly analyzed, it appears that the grain boundaries between the solid sulfide-based electrolyte particles disappear and the distribution of element becomes uniform with an increase in kneading time in the coating step, that is, 1 minute (Example 1)t 2 minutes (Example 2), 4 minutes (Example 3), 8 minutes (Example 4) and 30 minutes (Example 8). When Example 9 to Example 11 (FIG, 9A to FIG. 11B) are analyzed, it appears that the grain boundaries between solid sulfide-based electrolyte particles disappear and a distribution element becomes uniform with an increase in the kneading time in the coating step, that is, 10 minutes (Example 9), 20 minutes (Example 10) and 30 minutes (Example 11), Furthermore, when Example 9 to Example 11 (FIG, 9A to FIG. 11B) are compared to Example 1 to Example 4, and Example 8 (FIG. 4A to FIG 8B), it appears that an energy free surface is high because of no pretreatment step and, as a result, the solid sulfide-based electrolyte is easily coated with composite particles. So, it appears that an energy in which solid sulfide-based electrolyte plastically deforms is allowed to be more efficiently applied under the conditions of Example 9 to Example 11 where no pretreatment step is performed than under the conditions of Example 1 to Example 4, and Example 8 in which the pretreatment step is carried out.
[0128] Furthermore, when Example 12 and Example 13 (FIG. 12A to FIG. 13B) are compared with Example 1 to Example 4, and Example 8 to Example 11 (FIG. 4A to FIG. 11B), it appears that particles of Sulfide-based solid electrolytes are plastically bonded together with more deformation in Example 12 and Example 13, and the bright colored portion (niobium element, and the like) is completely coated with the dark colored portion (phosphor element, sulfur element, and similar). So, it appears that an energy which the solid sulfide-based electrolyte plastically deforms is allowed to be more efficiently applied under the conditions of Example 12 and Example 13 in which the solid sulfide-based electrolyte particles have an average particle diameter of 0. 8 µm were then used under the conditions of Example 1 to Example 4, and Example 8 to Example 11 in which solid sulfide-based electrolyte particles having an average diameter of 1.5 µm were used,
[0129] Furthermore, when Example 14 (FIG. 14A and FIG. 14B) is compared with Example 1 to Example 4, and Example 8 to Example 13 (FIG. 4A and FIG. 13B), the solid-based electrolyte particles' in sulfide are bonded together more fully in Example 14 than in the other examples and only the dark colored portion (phosphor element, sulfur element, and the like) is recognized in the electronic reflection image (FIG, 148), So , it appears that an energy at which the plastically deformed sulfide-based solid electrolyte is allowed to be more efficiently applied under the condition of Example 14 in which the sulfide-based solid electrolyte particles were placed three times separately in the re-coating step than under the conditions from Example 1 to Example 4, and Example 8 to Example 13 in which the sulfide-based solid electrolyte particles were placed at once in the coating step.
[0130]Then, the active material compound according to Example Reference 1, which uses natural graphite particles (active material particles) as a raw material, will be analyzed. As is apparent from the comparison between FIG, 15A and FIG, 20A, it appears that the surface of the natural graphite is coated with the solid sulfide-based electrolyte substantially without any gap in the active material compound according to Reference Example 1. As is apparent from a comparison between FIG. 15B© FIG. 20B, a darker colored portion (carbon element, and the like) is completely coated with a relatively bright colored portion (phosphorus element, sulfur element, and the like). For this reason, it appears that the surface of each natural graphite particle is sufficiently coated with the solid sulfide-based electrolyte containing a phosphorus element, and the like, in the active material compound according to Reference Example 1. 3. Assessment of Active Material Composite Coverage
[0131 ]The active material compound according to Example 1 to Example 14 and Comparative Example 1 were measured by X-ray photoelectronic spectrography (XPS), The details of the measurement method are as follows.
[0132] X-Ray Photoelectronic Spectrometer: Produced by Physical Electronics, Quantera SXM (product name)
[0133] X-ray source: Monochromatic AIK0
[0134] X-ray output: 44.8 W
[0135]X-ray beam size: 200 μmΦ
[0136]An element ratio (ER) was calculated from the peak cross-sectional area of each element in the obtained XPS spectrum. The obtained element proportion (ER) was substituted into the following mathematical expression (B1), and the coverage was calculated. The result is shown in Table 1.
[0137] Coverage = (ERP + ERS + ERf)/(ERMn + ERNj + ERNb + ERP + ERs + ERj) (B1)
[0138](In the mathematical expression above (B1), ERP denotes the element proportion of a phosphorus element, ERs denotes the element proportion of a sulfur element, ER( denotes the element proportion of an iodine element, ER^ n denotes the element ratio of a manganese element, ERco denotes the element ratio of a cobalt element, ERNI denotes the element ratio of a nickel element, and ERNb denotes the element ratio of a niobium element.
[0139]FIG, 16 is a graph showing the correlation between the coverage of the sulfide-based solid electrolyte in each of the active material compounds according to Example 1 to Example 14 and Comparative Example 1 and the kneading time in the coating step. As shown in FIG. 16, the active material compound according to Example 1 to Example 14 in which the coating step was carried out each has a higher coverage of the sulfide-based solid electrolyte than the active material compound according to Comparative Example 1 in which the coating step was carried out. It appears from FIG. 16 that, in the active material compound according to Example 1 to Example 8 in which the pretreatment step was carried out, the coating of the solid sulfide-based electrolyte improves with kneading time in the coating step extends but improves in solid sulfide-based electrolyte coverage for an upper limit of 88% for kneading time of 25 minutes or more. It appears from FIG. 16 that, in the active material compound according to Example 9 to Example 11 in which no pretreatment step was carried out and sulfide-based solid electrolyte particles having an average particle diameter of 1.5 µm were also used , the coverage of the solid sulfide-based electrolyte improves as the kneading time in the coating step extends but does not improve the coverage of the solid sulfide-based electrolyte to an upper limit of 93% for the kneading time of 20 minutes or more . When examples of the same kneading time are compared to each other, the coverage of the sulfide-based solid electrolyte is higher in Example 10 (kneading time: 20 minutes) than in Example 7 (kneading time: 20 minutes), and the coverage of the solid sulfide-based electrolyte is higher in Example 11 (kneading time: 30 minutes) than in Example 8 (kneading time: 30 minutes), The active material compound according to Example 12 to Example 14 in which no pre-treatment steps were performed and the sulfide-based solid electrolyte particles having an average particle diameter of 0.8 µm were used having a higher sulfide-based solid electrolyte coverage by 4% or more than the composite material active according to Example 1 to Example 11. Among others, the active material compound according to Example 14 exhibited the highest coverage of the solid sulfide-based electrolyte, which is 99.0%. 4. Secondary Lithium Battery Manufacturing
[0140] From now on, lithium secondary batteries were respectively manufactured using the active material compound described above according to Example 1 to Example 14 and Comparative Example 1. Any of the active material compounds described above were prepared as the positive electrode active material, 48.5Lí2S-17.5P2S5-4Li2O-30Lil particles were prepared as solid sulfide-based electrolyte, steam grown carbon fiber (VGCF) was prepared as the electrically conductive material, and PVdF was prepared as the binder . These active materials of the positive electrode, solid sulfide-based electrolyte, electrically conductive material and connector were mixed such that the active material of the positive electrode: solid sulfide-based electrolyte: electrically conductive material: Ligator - 79.3 percent by weight: 17.1 percent by weight: 2.4 percent by weight: 1.2 percent by weight. Then, a positive electrode mix was prepared. Particles of 48.5Li2S-17.5P2S5-4Li2θ-30Lil which are the sulfide-based solid electrolyte were prepared as a separating layer raw material (solid electrolyte layer). Natural graphite was prepared as the electrode negative active material, 48.5Li2S-17.5P2S5-4Li2O~30Ui particles were prepared as the sulfide-based solid electrolyte, and PVdF was prepared as the binder. in sulfide and binder were mixed such that active material of the negative electrode: solid sulfide-based electrolyte: Ligator = 57.0 percent by weight: 41.6 percent by weight: 1.4 percent by weight. Then, a negative electrode mixture was prepared. First, a green compact of 48.5LI2S-17.5P2S5-4LI2O-30LII particles were formed. Subsequently, the positive electrode mixture was arranged on one face of the green compact, the negative electrode mixture was arranged on the other face, and they were subjected to a flat press for a pressing time of 1 minute under a pressing pressure of 6 ton /cm2. So, a laminated body was obtained. In the laminated body obtained at this time, the thickness of the positive electrode mixing layer and the thickness of the negative electrode mixing layer each t and 130 µm, and the thickness of the separating layer was 20 µm. By restricting the laminated body under pressure of 0.2 N in the laminated direction, the secondary lithium battery was manufactured. Hereinafter, secondary lithium batteries1 which respectively use the active material compounds according to Example 1 to Example 14 and Comparative Example 1 as raw materials are respectively referred to as secondary lithium batteries according to Example 1 to Example 14 and Comparative Example 1. 5. Measurement of Lithium Secondary Battery Reaction Resistance
[0141 JFor each of the secondary lithium batteries according to Example 4, Example 8, Example 10 to Example 14 and Comparative Example 1, the reaction resistance was measured by high-frequency impedance method. measurement are as follows.
[0142] Voltage Amplitude: 10 mV
[0143] Frequency: 1 MHz to 0.1 Hz
[0144] Voltage: 3.52 V
[0145]FIG, 18 is a schematic view of a Nyquist diagram that is obtained using the high frequency impedance method. Assessments were made by defining a circular arc component indicating the variation with the double-headed arrow in FIG. 18 as a reaction resistor.
[0146]Table 1 shows various manufacturing conditions of the active compound materials according to Example 1 to Example 14, Reference Example 1 and Comparative Example 1, the coating of the solid sulfide-based electrolyte in each active material compound and the resistance reaction of each secondary lithium bacteria.


[0147] FIG. 17 is a graph showing the correlation between the sulfide-based solid electrolyte coating on each of the active material compounds according to Example 4, Example 8, Example 10 to Example 14, and Comparative Example 1 and the strength of reaction of a corresponding secondary lithium batteries using the active material compounds. As shown in FIG. 17, each of the secondary lithium batteries according to Example 4, Example 8, and Example 10 to Example 14 has a lower reaction resistance than the secondary lithium battery according to Comparative Example 1. So, it looks like the compound of active material according to the invention, obtained through the coating step, has the function of reducing the reaction resistance of the secondary lithium battery as compared to the existing active material compound. As shown in FIG. 17, when the coverage of the sulfide-based solid electrolyte is 93%, the secondary lithium battery reaction resistance has a local minimum value (10 Q.cm2), When the coverage of the active compound material is within the range greater than or equal to 85% and less than or equal to 95%, the reaction resistance of the secondary lithium battery is less than or equal to 12 ilcm2. The reason why the reaction resistance exceeds 12 Q.cm2 when the coverage of the active material compound exceeds 95% is presumably that a probability of contact between an electrically conducting aid, which is the electrode material, and the active material particles they decrease and the electron-conducting pathway is interrupted and, as a result, resistance increases.

权利要求:
Claims (8)
[0001]
1. Active material composite comprising: composite particles containing active material particles and a solid oxide-based electrolyte, active material particles containing at least any one of a cobalt element, a nickel element and a manganese element and further containing a lithium element and an oxygen element, the solid oxide-based electrolyte coating all or part of a surface of each of the active material particles; and a solid sulfide-based electrolyte still coating 76.0% or more and 99% or less of a surface of each of the composite particles; CHARACTERIZED by the fact that the compound having an alkyl group is adhered to the surface of each compound particle and/or the surface of the solid sulfide-based electrolyte.
[0002]
2. Composite of active material, according to claim 1, CHARACTERIZED by the fact that the solid sulfide-based electrolyte coats 85% or more and 95% or less of the surface of each of the composite particles.
[0003]
3. Manufacturing method for an active material composite, CHARACTERIZED by the fact that it comprises: a preparation step of preparing composite particles containing active material particles and a solid oxide-based electrolyte, the active material particles containing at least any one of a cobalt element, a nickel element and a manganese element and further containing a lithium element and an oxygen element, the solid oxide-based electrolyte coating all or part of a surface of each of the active material particles; and a coating step of coating 76.0% or more and 99% or less of a surface of each of the composite particles with a solid sulfide-based electrolyte by mixing the composite particles with the solid sulfide-based electrolyte with application of an energy, in that the solid sulfide-based electrolyte plastically deforms, while a temperature of a mixture of the composite particles and the solid sulfide-based electrolyte is set at 100°C or below.
[0004]
4. Method of fabrication according to claim 3, CHARACTERIZED by the fact that in the coating step, sulfide-based solid electrolyte particles having an average particle diameter of 1 µm or less are used as the electrolyte sulfide-based solid.
[0005]
5. Manufacturing method according to claim 3 or 4, CHARACTERIZED by the fact that in the coating step, the solid sulfide-based electrolyte is further added to the mixture after mixing for 10 minutes or more, and is mixed with application of energy, in which the solid sulfide-based electrolyte plastically deforms while the temperature of the mixture is adjusted to 100°C or below.
[0006]
6. Method of fabrication according to claim 3 or 4, CHARACTERIZED by the fact that it further comprises: a pre-treatment step of mixing at least one of the composite particles and the solid sulfide-based electrolyte with a compound having a alkyl group before the coating step.
[0007]
7. Method of fabrication, according to claim 3, CHARACTERIZED by the fact that in the coating step, the solid sulfide-based electrolyte is further added to the mixture after mixing for 10 minutes or more, and is mixed with application of energy, in which the solid sulfide-based electrolyte plastically deforms while the temperature of the mixture is adjusted to 100°C or below; and the method further comprises: a step of pre-treatment of mixing at least one of the composite particles and the solid sulfide-based electrolyte with a compound having an alkyl group prior to the coating step.
[0008]
8. Secondary lithium battery CHARACTERIZED by the fact that it comprises: a positive electrode; a negative electrode; and an electrolyte layer interposed between the positive electrode and the negative electrode, in which at least one of the positive electrode and the negative electrode contains at least one of the active material compound, as defined in claim 1 or 2, and the material compound asset manufactured in accordance with the method of manufacture as defined in any one of claims 3 to 7.

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公开号 | 公开日

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EP2954575B1|2016-09-28|

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CN104969386B|2017-04-19|

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US9929430B2|2018-03-27|

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AU2014213750B2|2016-07-14|

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TW201440300A|2014-10-16|

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CN104969386A|2015-10-07|

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BR112015018684A2|2017-07-18|

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CA2900419C|2018-07-24|

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TWI523303B|2016-02-21|

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AU2014213750A1|2015-08-20|

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WO2014122520A1|2014-08-14|

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EP2954575A1|2015-12-16|

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CA2900419A1|2014-08-14|

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US20150372344A1|2015-12-24|

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KR101800945B1|2017-11-23|

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JP2014154407A|2014-08-25|

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JP5725054B2|2015-05-27|

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KR20150103741A|2015-09-11|

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法律状态:
2018-02-27| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|

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2019-10-22| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|

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2021-06-01| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|

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2021-08-17| B16A| Patent or certificate of addition of invention granted [chapter 16.1 patent gazette]|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 06/02/2014, OBSERVADAS AS CONDICOES LEGAIS. |

优先权:

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申请号 | 申请日 | 专利标题

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JP2013-023890|2013-02-08|

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JP2013023890A|JP5725054B2|2013-02-08|2013-02-08|Composite active material and method for producing the same|

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PCT/IB2014/000119|WO2014122520A1|2013-02-08|2014-02-06|Composite active material, manufacturing method for composite active material, and lithium secondary battery including composite active material|

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