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    • 专利摘要:
    The invention relates to a process for the preparation of a vanadium-carbon phosphate composite material, a vanadium-carbon phosphate composite material obtained according to the method, and to the uses of said composite material, especially as a precursor for the synthesis of electrochemically active materials. electrode or active anode material.
    公开号:FR3062384A1
    申请号:FR1750832
    申请日:2017-02-01
    公开日:2018-08-03
    发明作者:Renald David；Christine SURCIN；Mathieu Morcrette
    申请人:Centre National de la Recherche Scientifique CNRS；
    IPC主号:
    专利说明:

    Holder (s): NATIONAL CENTER FOR SCIENTIFIC RESEARCH Public establishment.
    O Extension request (s):
    Agent (s): simplified.
    CABINET LAVOIX Joint-stock company ® PROCESS FOR THE PREPARATION OF A COMPOSITE MATERIAL VANADIUM-CARBON PHOSPHATE BY LIQUID ROUTE.
    @) The invention relates to a process for the preparation of a vanadium-carbon phosphate composite material, a vanadium-carbon phosphate composite material obtained according to said process, as well as the uses of said composite material, in particular as a precursor for the synthesis of materials. electrochemically active electrode or as active anode material.
    FR 3,062,384 - A1
    LIQUID PROCESS FOR THE PREPARATION OF A VANADIUM CARBON PHOSPHATE COMPOSITE MATERIAL
    The invention relates to a process for the preparation of a vanadium-carbon phosphate composite material, a vanadium-carbon phosphate composite material obtained according to said process, as well as the uses of said composite material, in particular as a precursor for the synthesis of electrochemically active materials. electrode or as an anode active material.
    It applies in particular to the field of lithium-ion or sodium-ion batteries, in which there is a growing demand for active materials for electrodes which can be obtained according to a simple and economical process, while guaranteeing good electrochemical performance.
    A lithium battery (respectively a sodium battery) comprises at least one negative electrode and at least one positive electrode between which is placed a solid electrolyte or a separator impregnated with a liquid electrolyte. The liquid electrolyte for example consists of a lithium salt (respectively a sodium salt) in solution in a solvent chosen to optimize the transport and dissociation of the ions. The positive electrode consists of a current collector supporting an electrode material which contains at least one active positive electrode material capable of reversibly inserting lithium ions (respectively sodium ions); the negative electrode consists of a sheet of lithium (respectively sodium) metal (possibly supported by a current collector), of a lithium alloy (respectively of sodium) or of an intermetallic compound of lithium (respectively of sodium ) (lithium battery) (respectively sodium battery), or by a current collector supporting an electrode material which contains at least one negative electrode active material capable of inserting lithium ions (respectively sodium ions) of reversible (lithium ion battery: Li-ion) (sodium ion battery: Na-ion respectively). Each electrode material generally further comprises a polymer which acts as a binder (eg poly (vinylidene fluoride) or PVdF) and / or an agent conferring electronic conductivity (eg carbon) and / or a compound conferring ionic conduction (eg lithium salt) (eg sodium salt respectively).
    During the operation of the battery, lithium ions (respectively sodium ions) pass from one to the other of the electrodes through the electrolyte. During the discharge of the battery, an amount of lithium (respectively of sodium) reacts with the active material of positive electrode from the electrolyte, and an equivalent amount is introduced into the electrolyte from the active material of the negative electrode, the lithium (respectively sodium) concentration thus remaining constant in the electrolyte. The insertion of lithium (respectively sodium) into the positive electrode is compensated by supply of electrons from the negative electrode via an external circuit. During charging, the reverse phenomena take place.
    Several methods are known for preparing a material based on vanadium phosphate and carbon. For example, Zhang et al. [J. Alloys and Compounds, 2012, 522, 167-171] have described a sol-gel process for forming a composite material comprising vanadium phosphate coated with an amorphous carbon film of thickness approximately 8 nm. More particularly, V 2 O 5 and oxalic acid in stoichiometric quantities are dissolved in water with stirring for 1 h at 70 ° C. Then, NH4H2PO4 in stoichiometric quantities is added to the preceding mixture at 70 ° C and the resulting mixture is maintained at 70 ° C for 4 h until the formation of a gel. The gel obtained is then dried at 100 ° C for 12 h, to form a powder which is pressed in the form of pellets. The pellets are then heated at 350 ° C for 4 h under argon and glucose as a carbon source is ground with the pellets. The resulting mixture is finally calcined at 750 ° C for 12 hours under argon. However, this type of process comprises a large number of steps and remains very long. Furthermore, the intimate grinding step between the vanadium phosphate precursor and the glucose is decisive for obtaining a homogeneous carbon coating. Finally, this process uses NH4H2PO4 which produces ammonia, making it difficult to industrialize.
    Furthermore, Barker et al. described in US2002 / 0192553 the reduction by carbothermal of V 2 O 5 in the presence of NH 4 H 2 PO 4 and acetylene black at 300 ° C for 3 h in air, the cooling of the resulting mixture, its grinding, then its calcination at 750 ° C for 8 hours under argon. The use of excess carbon makes it possible to result in a material comprising vanadium phosphate and carbon. However, the material is in the form of micrometric grains of carbon mixed with micrometric grains of vanadium phosphate. It therefore has electrochemical performances which are not optimized (cf. example 4 as described below). An alternative to carbothermic reduction is the use of dihydrogen as a reducing agent. In particular, a mixture of V 2 O 5 and NH 4 H 2 PO 4 is heated to 300 ° C for 8 h under dihydrogen, cooled, ground, then heated to 850 ° C for 8 h under dihydrogen. However, the vanadium phosphate must then be contacted with a carbon source such as glucose in an additional step. In addition, NH 4 H 2 PO 4 releases dinitrogen under a reducing atmosphere which deteriorates the walls of the apparatus / reactors used. Finally, the grinding or mechanosynthesis steps used in the aforementioned processes are expensive.
    The hydrothermal route has also been proposed to produce a material based on vanadium phosphate and possibly carbon. However, this route requires the use of very high pressures and / or an autoclave which increases the production cost.
    The object of the present invention is therefore to overcome all or part of the drawbacks of the aforementioned prior art, and in particular to provide a simple process (eg which comprises few steps) and inexpensive for the preparation of a composite material based on vanadium phosphate and carbon, while avoiding the release of harmful gases such as ammonia.
    The first object of the invention is therefore a process for the preparation of a composite material of vanadium and carbon phosphate corresponding to the formula VPO 4 / C, characterized in that it comprises the following steps:
    i) the mixture of a vanadium precursor, H 3 PO 4 , of a compound comprising at least one carboxylic acid function in an aqueous solvent, it being understood that when the compound comprising at least one carboxylic acid function is different from a carbon precursor, the mixture further comprises a carbon precursor compound, ii) heating the mixture of step i) at a temperature ranging from 35 ° C. to approximately 100 ° C., in order to form a solid residue, and iii ) heating the solid residue to a temperature above about 850 ° C.
    Thus, the method of the invention allows in a few steps and economically, to directly form a composite material of vanadium and carbon phosphate, while avoiding the release of harmful gases such as ammonia.
    Step i) is generally carried out at a temperature ranging from 15 to 30 °, and preferably from 20 to 25 ° C (i.e. room temperature).
    It makes it possible to form an aqueous suspension comprising the vanadium precursor, H 3 PO 4 (as phosphate precursor), a compound comprising at least one carboxylic acid function and optionally a carbon precursor compound.
    In the process, the compound comprising at least one carboxylic acid function acts as a chelating agent. Furthermore, the compound comprising at least one carboxylic acid function or the carbon precursor compound will make it possible to form a carbon layer enveloping the particles of VPO 4 .
    The compound comprising at least one carboxylic acid function can be identical to or different from a carbon precursor. When the compound comprising at least one carboxylic acid function is also a carbon precursor, it plays the role of both a chelating agent and a carbon precursor. The addition of a carbon precursor compound is therefore not necessary. When the compound comprising at least one carboxylic acid function is not a carbon precursor, a carbon precursor compound must be used.
    According to a particularly preferred embodiment of the invention, the compound comprising at least one carboxylic acid function is a polycarboxylic acid, and more preferably it comprises two or three carboxylic acid functions.
    In a particular embodiment, the compound comprising at least one carboxylic acid function comprises from 2 to 10 carbon atoms, and preferably from 2 to 6 carbon atoms.
    The compound comprising at least one carboxylic function can also contain one or more hydroxyl functions, in particular in position a of a carboxylic acid function.
    The compound comprising at least one carboxylic acid function can be chosen from saturated carboxylic or polycarboxylic acids such as oxalic acid, citric acid, glycolic acid, lactic acid, tartaric acid, malic acid , succinic acid, glycolic acid, malonic acid, glutaric acid, adipic acid, isocitric acid, oxalosuccinic acid, tricarballylic acid and unsaturated carboxylic or polycarboxylic acids such as l maleic acid, fumaric acid and aconitic acid.
    Saturated carboxylic or polycarboxylic acids are preferred.
    The aqueous solvent is preferably water, especially distilled water.
    The vanadium precursor is preferably V 2 O 5 .
    The molar ratio [H 3 PO 4 / vanadium element in the vanadium precursor] generally varies from 1 to 1.5 approximately.
    The molar ratio [compound comprising at least one carboxylic acid / vanadium element function in the vanadium precursor] is generally at least 1, and preferably varies from 1 to 2 approximately, and more preferably from 1.02 to 1, 5 approx. This thus optimizes the electrochemical performance.
    The mass concentration of vanadium precursor (eg V 2 O 5 ) in the aqueous suspension at the end of step i) varies from 0.1% to 25% by mass approximately, and preferably from 0.5 to 15 % by mass approximately.
    The carbon precursor compound can be a polyol such as a diol or a triol.
    According to a particularly preferred embodiment of the invention, the carbon precursor compound is chosen from ethylene glycol and glycerol.
    The molar ratio [carbon precursor compound / vanadium element in the vanadium precursor] preferably ranges from approximately 0.05 to 2, and more preferably from approximately 0.25 to 0.45.
    According to a particularly preferred embodiment of the invention, the mixture of step i) comprises either citric acid (as compound comprising at least one carboxylic acid and carbon precursor function), or oxalic acid (as a compound comprising at least one carboxylic acid function) and ethylene glycol or glycerol (as a carbon precursor compound).
    Stage i) generally lasts from 1 to 60 min approximately.
    Step i) is preferably a mechanical mixture.
    The mixture of step i) may also comprise a polyol such as a diol or a triol, in particular when the compound comprising at least one carboxylic acid function is a carbon precursor.
    The polyol can be chosen from ethylene glycol and glycerol.
    The mixture of step i) can also comprise a binder.
    The binder can make it possible to avoid taking up volume during the implementation of the method of the invention, and thus can make it possible to freeze the system, making it easily industrializable.
    The binder can be chosen from synthetic polymers such as polyvinyl alcohol, polyethylene glycol, polyvinylpyrrolidone, polyacrylonitrile, polyformaldehyde, polylactic acid or polyitaconates; biopolymers such as polysaccharides, polysaccharide derivatives or polypeptides; and one of their mixtures.
    By way of example of polysaccharide derivatives, mention may in particular be made of agar-agar.
    Step ii) evaporates the aqueous solvent to form a solid residue.
    Stage ii) is generally carried out in air, in particular using a heating plate.
    In a particular embodiment, step ii) lasts from ih to 12 hours approximately.
    Step ii) is preferably carried out with magnetic stirring.
    Steps i) and ii) can be concomitant.
    Step iii) preferably lasts at least about 30 minutes, and more preferably at least about 1 hour.
    In a particular embodiment, step iii) lasts at most about 8 hours, preferably at most about 5 hours, and more preferably at most about 3 hours.
    Indeed, this maximum duration makes it possible to avoid the formation of by-products such as vanadium phosphite (VP).
    Step iii) is preferably carried out at a temperature above 860 ° C, and more preferably between 880 ° C and 900 ° C approximately.
    Step iii) can be carried out under argon or in air.
    Step iii) can be carried out in a closed or open container.
    The method can also comprise a step iv) during which the composite material obtained at the end of step iii) is cooled, in particular to ambient temperature (i.e. approximately 20-25 ° C.).
    Step iv) can be carried out using water, and preferably cold water (cold water temperature below room temperature, e.g. less than about 20-25 ° C).
    The process preferably does not include any step (s) of grinding and / or mechanosynthesis (well known under Anglicism "bail milling").
    The process may further comprise step ii ') between steps ii) and iii) during which the solid residue is heated to a temperature of approximately 200 to 400 ° C., in particular for a period of 30 minutes to approximately 2 hours.
    This step ii ′) can be carried out in an oven.
    Step ii ') can make it possible to contain a possible increase in volume in an open environment.
    The process preferably does not include any other heating step (s) than steps ii), ii ') and iii).
    The process preferably does not include the use of high pressures (e.g. pressures of the order of 3 bars) and / or the use of an autoclave.
    The second object of the invention is a composite material of vanadium and carbon phosphate, characterized in that it is obtained according to a process in accordance with the first object of the invention.
    In particular, the composite material of the invention comprises particles of VPO 4 coated with a layer of amorphous carbon.
    The composite material of vanadium and carbon phosphate of the invention has the advantage of leading to electrochemically active materials of electrodes which have improved electrochemical performance compared to those obtained from a material of vanadium phosphate and carbon of the prior art.
    A third object of the invention is therefore the use of a composite material of vanadium and carbon phosphate as obtained according to the process according to the first subject of the invention as a precursor for the preparation of electrochemically active materials of electrodes. , and in particular active materials of polyanionic type cathodes such as Na 3 V 2 (PO4) 2F3 / C, Na 3 V 2 (PO4) 3 / C or LiVPO 4 F / C.
    A fourth object of the invention is the use of a composite material of vanadium and carbon phosphate as obtained according to the process in accordance with the first subject of the invention as an active anode material.
    The fifth object of the invention is a composite material of formula Na 3 V 2 (PO 4 ) 2F3 / C, characterized in that it is obtained from a composite material of vanadium phosphate and carbon of formula VPO 4 / C in accordance with the second object of the invention or obtained according to a process in accordance with the first object of the invention.
    The composite material preferably has the following mesh parameters: a = 9.0294 (2) Â, b = 9.0445 (2) Â, c = 10.7528 (2) Â in the Amam crystal system.
    The invention has for sixth object a composite material of formula Na 3 V 2 (PO 4 ) 2F3 / C, characterized in that it has the following lattice parameters: a = 9.0294 (2) Â, b = 9 , 0445 (2) Â, c = 10.7528 (2) Â in the Amam crystal system.
    This composite material can be obtained from a composite material of vanadium phosphate and carbon of formula VPO 4 / C in accordance with the second subject of the invention or obtained according to a process in accordance with the first subject of the invention.
    EXAMPLES
    The raw materials used in the examples are listed below:
    - H3PO4, Alfa Aesar, 85% in water,
    - V 2 O 5 , Alfa Aesar, 99.2%,
    - citric acid, Alfa Aesar, 99 +%,
    - oxalic acid, Sigma Aldrich, 98%,
    - ethylene glycol, Fluka,> 99.5%,
    - Na 3 PO 4 , Acros Organic, pure anhydrous,
    - NaF, Sigma Aldrich,> 99%,
    - distilled water, and
    - argon 5.0, Messer.
    Unless otherwise specified, all materials have been used as received from the manufacturers.
    Example 1
    Preparation of a composite material 1 of formula VPO 4 / C according to the process according to the invention
    4.04 g of vanadium oxide (V 2 O 5 ), 5.12 g of phosphoric acid (H3PO4), 4.2 g of oxalic acid and 0.9 g of ethylene glycol were mixed in a beak with 20 ml of distilled water.
    The resulting mixture was heated to 85 ° C with magnetic stirring for 12 h in order to evaporate the water. The residue obtained was heated to 890 ° C for 1 h in a quartz tube under an argon atmosphere.
    The tube was then cooled to room temperature using water.
    The composite material 1 obtained in the form of a powder was analyzed by X-ray diffraction (DRX) using a diffraction meter sold under the trade name D8 by the company Bruker (CuKa radiation). The samples were scanned between 16 and 50 ° 20.
    FIG. 1 represents an X-ray diffraction diagram of the composite material 1 of formula VPO 4 / C.
    All the diffraction peaks in Figure 1 have been indexed in the Cmcm crystal system with the following lattice parameters: a = 5.2399 (4) Â, b = 7.7886 (6) Â, and c = 6.2956 (4) Â, which agrees with the description given by Glaum et al. [Zeitschrift fuer Kristallographie (1979-2010), 1992, 198, 41-47],
    The amount of carbon in composite material 1 of formula VPO4 / C was analyzed by thermogravimetric analysis (ATG). A heating rate of approximately 10 ° C per minute was used from 25 ° C to approximately 680 ° C and a plateau at 680 ° C for 1 h was achieved. The composition of the gas phase was checked in parallel with the heating by mass spectroscopy (MS). It was approximately 4.8% by mass, relative to the total mass of composite material.
    The composite material 1 was also analyzed by transmission electron microscopy (TEM) using a microscope sold under the trade name FEI TECNAI G2 by the company FEI.
    FIG. 2 represents an image by TEM of the composite material 1. It confirms the presence of a carbon shell with a thickness of approximately 5 nm, enveloping the vanadium phosphate.
    Example 2
    Preparation of a composite material 2 of formula VPO 4 / C according to the process according to the invention
    4.04 g of vanadium oxide (V 2 O 5 ), 5.12 g of phosphoric acid (H3PO4) and 5.6 g of citric acid were mixed in a beaker with 20 ml of distilled water.
    The resulting mixture was heated to 85 ° C with magnetic stirring for 12 h in order to evaporate the water. The residue obtained was heated to 890 ° C for 1 h in a quartz tube under an argon atmosphere.
    The tube was then cooled to room temperature using water.
    The composite material 2 obtained in the form of a powder was analyzed by X-ray diffraction (DRX) using a device as described in Example 1. The samples were scanned between 16 and 50 ° 20.
    The X-ray diffraction diagram of the composite material 2 of formula VPO 4 / C was similar to that as obtained for the composite material of Example 1 (cf. FIG. 1).
    The TEM image of the composite material 2 of formula VPO 4 / C was similar to that as obtained for the composite material of Example 1 (cf. FIG. 2).
    The amount of carbon in the composite material 2 of formula VPO4 / C was analyzed by ATG as in Example 1. It was approximately 4.5% by mass, relative to the total mass of composite material.
    Comparative example 3
    Preparation of a material A according to a process not in accordance with the invention
    4.04 g of vanadium oxide (V 2 O 5 ), 5.12 g of phosphoric acid (H3PO4), 4.2 g of oxalic acid and 0.9 g of ethylene glycol were mixed in a beak with 20 ml of distilled water.
    The resulting mixture was heated to 85 ° C with magnetic stirring for 12 h in order to evaporate the water. The residue obtained was heated to 850 ° C for 10 h in a quartz tube under an argon atmosphere.
    The tube was then cooled to room temperature using water.
    The material A obtained in the form of a powder was analyzed by X-ray diffraction (XRD) using a device as described in Example 1. The samples were scanned between 20 and 40 ° 20 .
    FIG. 3 represents an X-ray diffraction diagram of the material A, showing an amorphous material very different from the composite materials 1 and 2 obtained respectively in Examples 1 and 2.
    Example 4
    Use of a composite material of formula VPO 4 / C obtained according to a process in accordance with the invention as a precursor for the preparation of electrochemically active materials of electrodes
    4.1 Preparation of NasXAiPCUjzFs / C g of a composite material of formula VPO 4 / C as obtained in Example 1 were mixed with 1.22 g of NaF for 12 h using a space mixer of the type Turbula including a ball. Then, the resulting mixture was heated to 700 ° C for 1 h in a quartz tube under an argon atmosphere.
    The tube was then cooled to room temperature using water.
    The composite material 3 of formula Na 3 V 2 (PO 4 ) 2F 3 / C obtained in the form of a powder was analyzed by X-ray diffraction (DRX) using a device as described in l Example 1. The samples were scanned between 16 and 50 ° 20. The Rietveld model was used to refine the mesh parameters of the materials.
    FIG. 4 represents an X-ray diffraction diagram of the composite material 3 of formula Na 3 V 2 (PO 4 ) 2F 3 / C, as well as an image by TEM of said composite material 3.
    All the diffraction peaks of FIG. 4 were indexed in the Amam crystal system with the following lattice parameters: a = 9.0294 (2) Â, b = 9.0445 (2) Â, c = 10.7528 ( 2) Â, which agrees with the description given by Bianchini et al. [Chem. Mater., 2015, 27, 8, 3009-3020].
    By way of comparison, a composite material B of formula Na 3 V 2 (PO 4 ) 2F 3 / C was prepared from a VPO 4 / C obtained according to the method of Barker et al. [US2002 / 0192553, reduction by carbothermy, example l (a)].
    To do this, 5.40 g of V 2 O 5 , 6.83 g of NH 4 H 2 PO 4 and 0.76 g of SP carbon were mixed, ground and transformed into granules. Then the granules were heated in an oven in air to 300 ° C (temperature rise of 2 ° C per minute) then the heating was maintained at 300 ° C for 3 h and then at 800 ° C for 8 h. The resulting mixture was cooled to room temperature. A black powder of OPV 4 / C was thus obtained. The composite material B of formula Na 3 V 2 (PO 4 ) 2 F 3 / C was prepared from this OPV 4 / C according to the same procedure as that described for producing the composite material 3.
    The composite material 3 was analyzed from the point of view of its electrochemical performance and compared with the composite material B.
    To do this, electrochemical tests were carried out using cells of the button-cell type®. The electrodes in the form of a film were produced in air from formulated inks comprising 87.1% by mass of active material (ie composite material 3 or B), 7.7% by mass of carbon and 5.2% by mass of PVdF. The button cells were assembled in a glove box. The electrochemical cell included:
    - an electrode film comprising the active material (i.e. composite material 3 or B), as a positive electrode,
    - a sodium sheet, as a negative electrode,
    - glass fibers category Whatman GF / D category 1823070, as a separator interposed between the positive and negative electrodes, and
    a solution comprising a sodium salt NaPF 6 (approximately 1 mol / l) dissolved in a mixture of ethylene carbonate / dimethyl carbonate (ratio 1/1 by mass), and 3% by mass of fluoroethylene carbonate, to titer of liquid electrolyte.
    FIG. 5 shows the curve of potential vs Na (in volts) as a function of capacity (in mAh / g) with a current regime of 1 Na exchanged per hour between the composite material B (FIG. 5a) and the composite material 3 ( FIG. 5b) and the capacity curve (in mAh / g) as a function of the number of cycles of the composite material B (FIG. 5c) and of the composite material 3 (FIG. 5d).
    FIG. 5 clearly shows good cycling stability when the active material is prepared from the composite material obtained according to the process of the invention.
    4.2 Preparation of Na ^ XGiPO ^ WC g of OPV 4 as obtained in Example 1 were mixed with 1.59 g of Na 3 PO 4 for 12 h using a space mixer of the Turbula type comprising a ball. Then, the resulting mixture was heated to 810 ° C for 1 h in a quartz tube under an argon atmosphere.
    The tube was then cooled to room temperature using water.
    The composite material 4 of formula Na 3 V 2 (PO 4 ) 3 / C obtained in the form of a powder was analyzed by X-ray diffraction (DRX) using a device as described in example 1. The samples were scanned between 16 and 50 ° 2Θ.
    FIG. 6 represents an X-ray diffraction diagram of the composite material 4 of formula Na 3 V 2 (PO 4 ) 3 / C, as well as an image by TEM of said composite material 4.
    All the diffraction peaks of FIG. 6 have been indexed in the crystalline system R-3c with the following lattice parameters: a = 8.7217 (2) Â, b = 8.7217 (2) Â and c = 21, 8485 (7) Â, which agrees with the description given by Zatovsky et al. [Acta Crystallographica, Section E., Structure Reports Online, 2010, 66, 2, pil2-pi 12].
    By way of comparison, a composite material C of formula Na 3 V 2 (PO 4 ) 3 / C was prepared from a VPO 4 / C obtained according to the method of Barker et al. [US2002 / 0192553, reduction by carbothermy, example l (a)]. The OPV 4 / C was therefore prepared according to a process identical to that described in Example 4.1 above, then the composite material C of formula Na 3 V 2 (PO 4 ) 3 was prepared from this OPV 4 / C according to the same procedure as that described for producing the composite material 4.
    The composite material 4 was analyzed from the point of view of its electrochemical performance and compared with the composite material C.
    To do this, electrochemical tests were carried out using cells of the button-cell type®. The electrodes in the form of a film were produced in air from formulated inks comprising 85.5% (respectively 80%) by mass of composite material 4 (respectively by mass of composite material C), 9, 8% by mass of carbon (respectively 14.2%) by mass of carbon and 4.7% (respectively 5.8%) by mass of PVdF. Button cells were assembled in a glove box. The electrochemical cell included:
    - an electrode film comprising the active material (i.e. composite material 4 or C), as a positive electrode,
    - a sodium sheet, as a negative electrode,
    - glass fibers category Whatman GF / D category 1823070, as a separator interposed between the positive and negative electrodes, and
    a solution comprising a sodium salt NaPF 6 (approximately 1 mol / l) dissolved in a mixture of ethylene carbonate / dimethyl carbonate (ratio 1/1 by mass), and 3% by mass of fluoroethylene carbonate, to titer of liquid electrolyte.
    Figure 7 shows the curve of potential vs Na (in volts) as a function of capacity (in mAh / g) with a current regime of C / 10 of the composite material C (Figure 5a) and of the composite material 4 (Figure 5b ) and the capacity curve (in mAh / g) as a function of the number of cycles of the composite material C (FIG. 5c) and of the composite material 4 (FIG. 5d).
    FIG. 7 clearly shows good stability of cycling when the active material is prepared from the composite material obtained according to the method of the invention.
    4.3 Preparation of LiViPOUF / C g of OPV 4 as obtained in Example 1 were mixed with 0.68 g of LiF for 12 h using a space mixer of Turbula type comprising a ball. Then, the resulting mixture was heated to 700 ° C for 1 h in a quartz tube under an argon atmosphere.
    The tube was then cooled to room temperature using water.
    The composite material 5 of formula LiV (PO 4 ) F / C obtained in the form of a powder was analyzed by X-ray diffraction (DRX) using a device as described in Example 1. The samples were scanned between 16 and 50 ° 2Θ.
    FIG. 8 represents an X-ray diffraction diagram of the composite material 5 of formula LiV (PO 4 ) F / C, as well as an image by TEM of said composite material 5.
    All the diffraction peaks in FIG. 8 were indexed in the crystal system P1 with the following lattice parameters: a = 5.1751 (5) Â, b = 5.3041 (4) Â, c = 7.2481 ( 6) Â, a = 107.507 (4) °, β = 107.847 (5) ° and y = 98.450 (4) °, which is in agreement with the description given by Ateba Mba et al. [Chemistry of Materials, 2012, 24, 6, 1223-1234].
    By way of comparison, a composite material D of formula LiV (PO 4 ) F / C was prepared from a OPV 4 / C obtained according to the method of Barker et al. [US2002 / 0192553, reduction by carbothermy, example l (a)]. The OPV 4 / C was therefore prepared according to a process identical to that described in Example 4.1 above, then the composite material D of formula LiV (PO 4 ) F / C was prepared from this OPV 4 / C according to the same procedure as that described for producing the composite material 5.
    The composite material 5 was analyzed from the point of view of its electrochemical performance and compared with the composite material D.
    To do this, electrochemical tests were carried out using cells of the button-cell type®. The electrodes in the form of a film were produced in air from formulated inks comprising 86.5% (respectively 87.1%) by mass of composite material 5 (respectively by mass of composite material D), 8.7% by mass of carbon (respectively 7.7%) by mass of carbon and 4.8% (respectively 5.2%) by mass of PVdF. Button cells were assembled in a glove box. The electrochemical cell included:
    - an electrode film comprising the active material (i.e. composite material 5 or C), as a positive electrode,
    - a lithium sheet, as a negative electrode,
    - glass fibers category Whatman GF / D category 1823070, as a separator interposed between the positive and negative electrodes, and
    a solution comprising a sodium salt LiPF 6 (approximately 1 mol / l) dissolved in a mixture of ethylene carbonate / dimethyl carbonate (ratio 1/1 by mass), and 3% by mass of fluoroethylene carbonate, to titer of liquid electrolyte.
    FIG. 9 shows the curve of the potential vs Li (in volts) as a function of the capacity (in mAh / g) with a current regime of C of the composite material D (FIG. 9a) and of the composite material 5 (FIG. 9b) and the capacity curve (in mAh / g) as a function of the number of cycles of the composite material D (FIG. 9c) and of the composite material 5 (FIG. 9d).
    FIG. 9 clearly shows good cycling stability when the active material is prepared from the composite material obtained according to the method of the invention.
    权利要求:
    Claims (19)
    [1" id="c-fr-0001]
    1. Process for the preparation of a composite material of vanadium and carbon phosphate corresponding to the formula VPO 4 / C, characterized in that it comprises the following steps:
    i) the mixture of a vanadium precursor, H 3 PO 4 , of a compound comprising at least one carboxylic acid function in an aqueous solvent, it being understood that when the compound comprising at least one carboxylic acid function is different from a carbon precursor, the mixture further comprises a carbon precursor compound, ii) heating the mixture of step i) at a temperature ranging from 35 ° C to 100 ° C, in order to form a solid residue, and iii) heating the solid residue to a temperature above 850 ° C.
    [2" id="c-fr-0002]
    2. Method according to claim 1, characterized in that the vanadium precursor is V 2 O 5 .
    [3" id="c-fr-0003]
    3. Method according to claim 1 or 2, characterized in that the compound comprising at least one carboxylic acid function comprises from 2 to 10 carbon atoms.
    [4" id="c-fr-0004]
    4. Method according to any one of the preceding claims, characterized in that the compound comprising at least one carboxylic acid function is a saturated carboxylic or polycarboxylic acid chosen from oxalic acid, citric acid, glycolic acid, l lactic acid, tartaric acid, malic acid, succinic acid, glycolic acid, malonic acid, glutaric acid, adipic acid, isocitric acid, oxalosuccinic acid and l tricarballylic acid.
    [5" id="c-fr-0005]
    5. Method according to any one of the preceding claims, characterized in that the molar ratio [compound comprising at least one carboxylic acid / vanadium element function in the vanadium precursor] varies from 1 to 2.
    [6" id="c-fr-0006]
    6. Method according to any one of the preceding claims, characterized in that the carbon precursor compound is chosen from ethylene glycol and glycerol.
    [7" id="c-fr-0007]
    7. Method according to any one of the preceding claims, characterized in that the molar ratio [carbon precursor compound / vanadium element in the vanadium precursor] varies from 0.05 to 2.
    [8" id="c-fr-0008]
    8. Method according to any one of the preceding claims, characterized in that the mixture of step i) comprises:
    - either citric acid,
    - either oxalic acid and ethylene glycol or glycerol.
    [9" id="c-fr-0009]
    9. Method according to any one of the preceding claims, characterized in that the mixture of step i) further comprises a binder.
    [10" id="c-fr-0010]
    10. Method according to claim 9, characterized in that the binder is agar-agar.
    [11" id="c-fr-0011]
    11. Method according to any one of the preceding claims, characterized in that step iii) lasts at most 8 hours.
    [12" id="c-fr-0012]
    12. Method according to any one of the preceding claims, characterized in that step iii) is carried out at a temperature between 880 ° C and 900 ° C.
    [13" id="c-fr-0013]
    13. Composite material of vanadium and carbon phosphate, characterized in that it is obtained according to a process as defined in any one of the preceding claims.
    [14" id="c-fr-0014]
    14. Composite material of vanadium and carbon phosphate according to claim 13, characterized in that it comprises particles of VPO 4 coated with a layer of amorphous carbon.
    [15" id="c-fr-0015]
    15. Use of a composite material of vanadium and carbon phosphate obtained according to a process as defined in any one of claims 1 to 12, as a precursor for the preparation of electrochemically active materials of electrodes.
    [16" id="c-fr-0016]
    16. Use of a composite material of vanadium and carbon phosphate obtained according to a process as defined in any one of claims 1 to 12, as active anode material.
    [17" id="c-fr-0017]
    17. Composite material of formula Na 3 V 2 (PO 4 ) 2F3 / C, characterized in
    5 that it is obtained from a composite of vanadium and carbon phosphate of formula VPO 4 / C as defined in claim 13 or 14 or obtained according to a process as defined in any one of claims 1 to 12.
    [18" id="c-fr-0018]
    18. Composite material according to claim 17, characterized in that it has the following mesh parameters: a = 9.0294 (2) Â, b = 9.0445 (2) Â, c = 10.7528 (2 ) Â in the Amam crystal system.
    [19" id="c-fr-0019]
    19. Composite material of formula Na 3 V 2 (PO 4 ) 2F3 / C, characterized in that it has the following mesh parameters: a = 9.0294 (2) Â, b = 9.0445 (2) Â , c = 10.7528 (2) Â in the Amam crystal system.
    1/5
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    同族专利:
    公开号 | 公开日
    JP2020506148A|2020-02-27|
    EP3577068A1|2019-12-11|
    CN110770165A|2020-02-07|
    FR3062384B1|2021-02-12|
    KR20190140900A|2019-12-20|
    WO2018142082A1|2018-08-09|
    US20190393492A1|2019-12-26|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US20020192553A1|2001-04-06|2002-12-19|Jeremy Barker|Sodium ion batteries|
    CN102774821B|2012-07-30|2014-05-21|四川大学|Solid phase-hydrothermal preparation method for lithium vanadium phosphate|
    CN103594716A|2013-11-21|2014-02-19|天津工业大学|Method for preparing cathode material of sodium-ion battery, namely sodium vanadium fluorophosphates|
    CN103872324B|2014-03-28|2016-08-24|中南大学|A kind of petal-shaped lithium ion battery negative material VPO4preparation method|
    WO2017064189A1|2015-10-13|2017-04-20|Commissariat A L'energie Atomique Et Aux Energies Alternatives|Method for preparing a na3v22f3 particulate material|
    CN112421027B|2020-11-17|2022-02-11|常州大学|Surface modified porous hexagonal Na3V22F3Carbon-coated microsphere and preparation method and application thereof|
    CN112678787A|2020-12-28|2021-04-20|大连博融新材料有限公司|Composite vanadium phosphate with high crystal phase purity and low content of soluble high-valence vanadium, and preparation method and application thereof|
    CN112694076A|2020-12-28|2021-04-23|大连博融新材料有限公司|Method for repairing carbon composite vanadium phosphate|
    法律状态:
    2018-02-26| PLFP| Fee payment|Year of fee payment: 2 |
    2018-08-03| PLSC| Search report ready|Effective date: 20180803 |
    2020-02-28| PLFP| Fee payment|Year of fee payment: 4 |
    2021-02-26| PLFP| Fee payment|Year of fee payment: 5 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1750832A|FR3062384B1|2017-02-01|2017-02-01|PROCESS FOR THE PREPARATION OF A VANADIUM-CARBON PHOSPHATE COMPOSITE MATERIAL BY THE LIQUID ROUTE|
    FR1750832|2017-02-01|FR1750832A| FR3062384B1|2017-02-01|2017-02-01|PROCESS FOR THE PREPARATION OF A VANADIUM-CARBON PHOSPHATE COMPOSITE MATERIAL BY THE LIQUID ROUTE|
    JP2019541233A| JP2020506148A|2017-02-01|2018-02-01|Liquid method for making vanadium phosphate-carbon composites|
    US16/481,705| US20190393492A1|2017-02-01|2018-02-01|Liquid process for preparing a vanadium phosphate-carbon composite material|
    PCT/FR2018/050248| WO2018142082A1|2017-02-01|2018-02-01|Liquid process for preparing a vanadium phosphate-carbon composite material|
    KR1020197022282A| KR20190140900A|2017-02-01|2018-02-01|Liquid Method for Manufacturing Vanadium Phosphate-Carbon Composites|
    CN201880009629.9A| CN110770165A|2017-02-01|2018-02-01|Liquid process for preparing vanadium phosphate-carbon composites|
    EP18712940.8A| EP3577068A1|2017-02-01|2018-02-01|Liquid process for preparing a vanadium phosphate-carbon composite material|
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