A positive electrode composite material and preparation method, battery, and electrical device

Abstract

The present application discloses a positive electrode composite material and its preparation method, battery, and electrical device. The preparation method of the composite positive electrode material comprises: mixing and granulating a first sodium source, a ferrous salt, and a first phosphate, sintering, and performing a first ball milling to obtain dapoxite; chemically de-sodiumizing the dapoxite to obtain an intermediate phase FePO4; configuring a second sodium source, a vanadium source, a second phosphate, a fluorine source, and a reducing agent into a solution, adjusting to a preset pH value, and performing a hydrothermal reaction to synthesize a NASICON structure Na3V2(PO4)2O2F; mixing the intermediate phase FePO4 and the NASICON structure Na3V2(PO4)2O2F, and performing a second ball milling to obtain a composite positive electrode material. Through the process of "sintering-chemical de-sodiumizing-ball milling", an amorphous composite NASICON structure electrode material is prepared, and the amorphous phase transformation is completed by an external potential, with excellent rate performance and cycle performance.

Description

Technical Field

[0001] The present application belongs to the field of battery material technology, and specifically relates to a positive electrode composite material and a preparation method, a battery, and an electrical device. Background Art

[0002] Lithium-ion batteries are widely used in power, energy storage and other fields due to their advantages in energy density and cycle performance. However, the scarcity of lithium resources has prevented their large-scale use. Sodium-ion batteries have abundant raw materials, low cost, and similar working mechanisms to lithium-ion batteries, and are expected to be used in energy storage, base stations and other fields. The difference in the physical properties of sodium and lithium atoms inevitably affects sodium- and lithium-containing compounds. For example, lithium iron phosphate has advantages such as high specific energy, high operating voltage, and long cycle life, and has great application prospects in the field of lithium batteries. However, sodium-based materials with the same chemical composition, such as Maricite, are difficult to show electrochemical activity.

[0003] Research has found that polyanionic compounds, such as Na4Fe3(PO4)2(P2O7) and Na2FeP2O7, have excellent rate and cycle performance and are promising cathode materials. However, most compounds have difficulty in achieving their full capacity, i.e., they cannot release all the Na + , which also reduces the attractiveness of polyanions in sodium ion battery applications. Due to the demand for high energy density of battery cells, further research is needed on cathode materials with high capacity.

[0004] Therefore, how to improve the performance capacity of polyanion compounds and thus improve the electrical performance of sodium ion batteries is a problem that needs to be solved at present. Summary of the Invention

[0005] The present application provides a positive electrode composite material and a preparation method, a battery, and an electrical device, aiming to overcome the problems that existing polyanionic materials are difficult to fully exert their full capacity and have unsatisfactory cycle performance.

[0006] In one aspect, the present invention provides a method for preparing a composite cathode material, comprising the following steps:

[0007] The first sodium source, the ferrous salt and the first phosphate are mixed and granulated, sintered and subjected to a first ball milling to obtain dawsonite;

[0008] Chemically removing sodium from the dapoxite to obtain an intermediate phase FePO4;

[0009] A second sodium source, a vanadium source, a second phosphate, a fluorine source, and a reducing agent are prepared into a solution, the solution is adjusted to a preset pH value, and a hydrothermal reaction is performed to synthesize a NASICON structure Na3V2(PO4)2O2F;

[0010] The intermediate phase FePO4 and the NASICON structure Na3V2(PO4)2O2F are mixed and subjected to a second ball milling to obtain the composite positive electrode material.

[0011] In some embodiments, the first sodium source comprises at least one of sodium carbonate, sodium acetate, sodium hydrogen phosphate, sodium phosphate, or sodium hydroxide.

[0012] In some embodiments, the ferrous salt includes at least one of ferrous sulfate, ferrous stearate, ferrous nitrate, or ferrous chloride.

[0013] In some embodiments, the first phosphate comprises at least one of phosphoric acid, ammonium hydrogen phosphate, or ammonium dihydrogen phosphate.

[0014] In some embodiments, the second sodium source comprises at least one of sodium carbonate, sodium acetate, sodium hydrogen phosphate, sodium phosphate, or sodium hydroxide.

[0015] In some embodiments, the vanadium source includes at least one of ammonium metavanadate, vanadium oxide, or vanadium sulfate.

[0016] In some embodiments, the second phosphate comprises at least one of phosphoric acid, ammonium hydrogen phosphate, or ammonium dihydrogen phosphate.

[0017] In some embodiments, the fluoride source includes at least one of sodium fluoride or ammonium bifluoride.

[0018] In some embodiments, the reducing agent comprises at least one of citric acid or ascorbic acid.

[0019] In some embodiments, the molar ratio of the first sodium source, the ferrous salt, and the first phosphate is (0.9-1.2):1:1.

[0020] In some embodiments, the molar ratio of the second sodium source, the vanadium source, the second phosphate, the fluorine source, and the reducing agent is 3:2:2:(2-2.5):(2-2.2).

[0021] In some embodiments, the mass ratio of the intermediate phase FePO4 to the NASICON structure Na3V2(PO4)2O2F is (0.1-15):(85-99.9).

[0022] In some embodiments, the median particle size D of the mesophase FePO4 is 50 0.1~2μm.

[0023] In some embodiments, the median particle size D of the NASICON structure Na3V2(PO4)2O2F is 50 2~10μm.

[0024] In some embodiments, the sintering temperature is 350-480° C., and the holding time is 4-8 hours.

[0025] In some embodiments, the first ball milling has a rotation speed of 600-1000 rpm and a ball milling time of 8-12 h.

[0026] In some embodiments, the temperature of the hydrothermal reaction is 180-220° C., and the reaction time is 12-18 hours.

[0027] In some embodiments, the preset pH value is 6-7.

[0028] In some embodiments, the second ball milling has a rotation speed of 400 to 5000 rpm and a ball milling time of 2 to 4 hours.

[0029] In some embodiments, the step of chemically removing sodium from the dapoxite further comprises:

[0030] The dalphidite is dissolved in a solvent, and a desodiumizing agent is added to carry out a desodiumizing reaction.

[0031] In some embodiments, the sodium removal agent includes at least one of sodium persulfate, sodium hypochlorite, and tetrafluoroborate.

[0032] In some embodiments, the molar ratio of the dawsonite to the desodium agent is (1.0-1.5):1.

[0033] In some embodiments, the desodium reaction time is 4 to 24 hours.

[0034] On the other hand, an embodiment of the present application provides a composite positive electrode material prepared by the preparation method in any of the above embodiments, wherein the composite positive electrode material includes FePO4 and NASICON structure Na3V2(PO4)2O2F, and the mass ratio of FePO4 and NASICON structure Na3V2(PO4)2O2F is (0.1~15):(85~99.9).

[0035] An embodiment of the present application also provides a battery, comprising a positive electrode plate, wherein the positive electrode plate comprises a positive electrode collector and a positive electrode active material layer disposed on the positive electrode collector, wherein the positive electrode active material layer comprises the composite positive electrode material of any of the above embodiments.

[0036] The present application also provides an electrical device comprising the above-mentioned battery.

[0037] The preparation method of the composite positive electrode material provided by the present application comprises: mixing a first sodium source, a ferrous salt, and a first phosphate to form granules, sintering, and performing a first ball milling to obtain dawsonite; chemically removing sodium from the dawsonite to obtain an intermediate phase FePO4; configuring a second sodium source, a vanadium source, a second phosphate, a fluorine source, and a reducing agent into a solution, adjusting the solution to a preset pH value, and performing a hydrothermal reaction to synthesize a NASICON structure Na3V2(PO4) 4)2 O2F; the intermediate phase FePO4 and the NASICON structure Na3V2(PO4)2O2F are mixed and subjected to a second ball milling to obtain a composite positive electrode material. Through the "sintering-chemical sodium removal-ball milling" process, FePO4 and the NASICON structure Na3V2(PO4)2O2F are combined to prepare an amorphous phase composite NASICON structure electrode material. The amorphous phase transformation is completed by applying an external potential. The composite positive electrode material prepared by the preparation method provided in this application has a high ion diffusion rate and excellent rate performance and cycling performance. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present application are described clearly and completely below. Obviously, the embodiments described are only some of the embodiments of the present application, not all of them. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0039] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances. In the description of this application, the meaning of "multiple" is two or more, unless otherwise clearly specified and specifically limited. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more features.

[0040] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application.

[0041] In one aspect, the present invention provides a method for preparing a composite cathode material, comprising the following steps:

[0042] The first sodium source, the ferrous salt and the first phosphate are mixed and granulated, sintered and subjected to a first ball milling to obtain dawsonite;

[0043] Chemical desodiumization of dapoxite yields the intermediate phase FePO4;

[0044] The second sodium source, vanadium source, second phosphate, fluorine source and reducing agent are prepared into a solution, adjusted to a preset pH value, and subjected to a hydrothermal reaction to synthesize the NASICON structure Na3V2(PO 4)2 O2F;

[0045] The intermediate phase FePO4 and the NASICON structure Na3V2(PO4)2O2F are mixed and subjected to a second ball milling to obtain a composite positive electrode material.

[0046] Generally speaking, most polyanionic compounds are difficult to fully utilize their full capacity. The fundamental reason is that the upper voltage limit required to fully utilize the capacity is generally higher than 4.5V, and the alkali metal ions are easily released to cause structural collapse. Maricite-type materials generally behave as electrochemically inert materials. High-energy ball milling can be used to nanosize the materials and make them electrochemically active. By oxidizing in the liquid phase, the Maricite-type NaFePO4 material is completely de-sodiumized, and the nano-activated material is completed. At the same time, since the nano-FePO4 itself is electrochemically active, there is sodium ion deintercalation during the charge and discharge process. This process is a solid solution phase transition, and there is no obvious volume deformation, which can stabilize Na3V2(PO 4)2 O2F structure, realizes Na3V2(PO 4)2 The performance of O2F materials is optimized to improve the capacity and cycle performance of the battery. The preparation method provided in this application combines two ball millings with desodium reactions to achieve the preparation of a nano-scale FePO4 composite NASICON structure Na3V2(PO4)2O2F material, which improves the current sodium ion battery polyanion problems such as the inability to fully utilize the capacity and high volume deformation from the perspective of positive electrode composite materials. During the charge and discharge process, FePO4 completes the transformation to the amorphous phase, and through the compounding of the amorphous phase structure, the volume deformation is slowed down, which improves the cycle performance of the sodium ion battery, and the amorphous phase ion diffusion rate is high, which has a corresponding improvement on the rate performance of the material.

[0047] In some embodiments, the step of chemically removing sodium from dapoxite further comprises:

[0048] The ulexite is dissolved in a solvent, and a desodium agent is added to carry out a desodium reaction.

[0049] In some embodiments, the sodium removal agent includes at least one of sodium persulfate, sodium hypochlorite, and tetrafluoroborate.

[0050] In some embodiments, the molar ratio of dawsonite to the desodiumizing agent is (1.0-1.5):1. For example, the molar ratio of dawsonite to the desodiumizing agent can be any one of 1.0:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, or any range between two thereof, wherein the desodiumizing agent can provide a unit element valence change.

[0051] In some embodiments, the sodium removal reaction time is 4 to 24 hours. For example, the sodium removal reaction time can be any one of 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, 15 hours, 18 hours, 20 hours, 22 hours, and 24 hours, or a range between any two of these values. The sodium removal reaction time is affected by the type of sodium removal agent.

[0052] In some embodiments, the first sodium source includes at least one of sodium carbonate, sodium acetate, sodium hydrogen phosphate, sodium phosphate, or sodium hydroxide.

[0053] In some embodiments, the ferrous salt includes at least one of ferrous sulfate, ferrous stearate, ferrous nitrate, or ferrous chloride.

[0054] In some embodiments, the first phosphate includes at least one of phosphoric acid, ammonium hydrogen phosphate, or ammonium dihydrogen phosphate.

[0055] In some embodiments, the second sodium source includes at least one of sodium carbonate, sodium acetate, sodium hydrogen phosphate, sodium phosphate, or sodium hydroxide.

[0056] In some embodiments, the vanadium source includes at least one of ammonium metavanadate, vanadium oxide, or vanadium sulfate.

[0057] In some embodiments, the second phosphate includes at least one of phosphoric acid, ammonium hydrogen phosphate, or ammonium dihydrogen phosphate.

[0058] In some embodiments, the fluoride source includes at least one of sodium fluoride or ammonium bifluoride.

[0059] In some embodiments, the reducing agent comprises at least one of citric acid or ascorbic acid.

[0060] In some embodiments, the molar ratio of the first sodium source, the ferrous salt, and the first phosphate is (0.9-1.2):1:1. For example, it can be 0.9:1:1, 1.0:1:1, 1.1:1:1, or 1.2:1:1.

[0061] In some embodiments, the molar ratio of the second sodium source, the vanadium source, the second phosphate, the fluorine source, and the reducing agent is 3:2:2:(2-2.5):(2-2.2).

[0062] In some embodiments, the mass ratio of the intermediate phase FePO4 and the NASICON structure Na3V2(PO4)2O2F is (0.1-15):(85-99.9).

[0063] In some embodiments, the median particle size D of the mesophase FePO4 is 50 is 0.1 to 2 μm. It can be understood that the median particle size D of the intermediate phase FePO4 50 The value of (unit: μm) can be any value among 0.1, 0.5, 1, 1.5, 2 or a range between any two values. It can be understood that the median particle size D of the mesophase FePO4 is 50 Affects the capacity, particle size, and compaction of the cathode composite material. When the intermediate phase FePO4 meets the above value range, the cathode composite material has a relatively higher compaction and a higher capacity.

[0064] In some embodiments, NASICON structure Na3V2(PO 4)2 The median particle size D of O2F 50 2 to 10 μm, it is understood that the NASICON structure Na3V2(PO 4)2 The median particle size D of O2F 50 The value of (unit: μm) can be any value among 2, 4, 6, 8, 10 or a range between any two values.

[0065] In some embodiments, the sintering temperature is 350-480° C., and the holding time is 4-8 hours. For example, the sintering temperature can be any value of 350° C., 380° C., 400° C., 420° C., 450° C., or 480° C., or a range between any two values; and the holding time can be any value of 4 hours, 5 hours, 6 hours, 7 hours, or 8 hours, or a range between any two values.

[0066] In some embodiments, sintering the first sodium source, the ferrous salt, and the first phosphate is performed in a reducing atmosphere.

[0067] Furthermore, the reducing atmosphere is in the range of an argon-hydrogen mixed gas with a hydrogen gas volume fraction of 5%, which can ensure the purity of NaFePO4 and avoid oxidation of divalent iron.

[0068] In some embodiments, the first ball milling has a rotation speed of 600-1000 rpm and a ball milling time of 8-12 h.

[0069] In some embodiments, the temperature of the hydrothermal reaction is 180-220° C., and the reaction time is 12-18 hours.

[0070] In some embodiments, the preset pH value is 6-7.

[0071] It should be noted that when the temperature, time and preset pH range of the hydrothermal reaction meet the above requirements, the purity and particle size of the product can be guaranteed.

[0072] In some embodiments, the second ball milling has a rotation speed of 400 to 5000 rpm and a ball milling time of 2 to 4 hours.

[0073] The second embodiment of the present application provides a composite positive electrode material, which is prepared by the preparation method in any of the above embodiments. The composite positive electrode material includes FePO4 and NASICON structure Na3V2(PO4)2O2F, and the mass ratio of FePO4 and NASICON structure Na3V2(PO4)2O2F is (0.1~15):(85~99.9).

[0074] A third embodiment of the present application provides a battery, including a positive electrode plate, the positive electrode plate including a positive electrode collector and a positive electrode active material layer disposed on the positive electrode collector, the positive electrode active material layer including the composite positive electrode material of any of the above embodiments.

[0075] A fourth embodiment of the present application provides an electrical device comprising the aforementioned battery.

[0076] The following describes the cathode composite material, preparation method, and battery provided by the present application in conjunction with specific embodiments:

[0077] Example 1

[0078] This embodiment provides a positive electrode composite material, which is prepared by the following method:

[0079] S1. Weigh Na2CO3, FeSO4, and NH4H2PO4 according to the molar ratio of Na:Fe:P=1:1:1, dry-grind them in a ball mill (200 rpm for 2 h) and then granulate them. In an atmosphere of argon-hydrogen mixed gas with a hydrogen volume fraction of 5%, heat the mixture from room temperature to 400°C at a heating rate of 5°C / min and maintain the temperature for 8 h. Grind the product to obtain Maricite NaFePO4.

[0080] S2. Place the above-mentioned Maricite NaFePO4 in deionized water, add Na2S2O8 at a molar ratio of Na:S=1:2, stir at room temperature for 4 hours, centrifuge the suspension, and wash it with deionized water and anhydrous ethanol three times respectively, and dry it in a vacuum at 80°C for 8 hours to obtain FePO4 powder;

[0081] S3. Weigh Na2CO3, NH4VO3, NH4H2PO4, and NaF in a molar ratio of citric acid:V:Na:P:F=2:2:3:2:2, and add them in sequence to rapidly stirred deionized water, and add ammonia water to adjust the pH value of the solution to 6-7; transfer the prepared solution to a polytetrafluoroethylene liner in a reactor and react at 200°C for 12 hours; centrifuge the obtained product, wash it with deionized water and anhydrous ethanol three times, respectively, and vacuum dry it at 80°C for 8 hours to obtain Na3V2(PO4)2O2F powder;

[0082] S4. Weigh Na3V2(PO4)2O2F and FePO4 in a mass ratio of 85:15, mix them using a ball mill (ball milling at 450 rpm for 2 h) to obtain FePO4 composite Na3V2(PO4)2O2F material.

[0083] Example 2

[0084] The mass ratio of NNa3V2(PO4)2O2F and FePO4 was changed to 90:10, and the remaining steps were the same as those in Example 1.

[0085] Example 3

[0086] The mass ratio of Na3V2(PO4)2O2F and FePO4 was changed to 95:5, and the remaining steps were the same as those in Example 1.

[0087] Comparative Example 1

[0088] Na2CO3, NH4VO3, NH4H2PO4, and NaF were weighed according to the molar ratio of citric acid: V: Na: P: F = 2:2:3:2:2, and added in sequence to rapidly stirred deionized water. Ammonia water was added to adjust the pH value of the solution to 6-7; the prepared solution was transferred to a polytetrafluoroethylene liner in a reactor and reacted at 200°C for 12 hours; the obtained product was centrifuged and washed three times with deionized water and anhydrous ethanol, respectively, and vacuum dried at 80°C for 8 hours to obtain Na3V2(PO4)2O2F powder.

[0089] The following is a battery assembly method. Example 1, Example 2, Example 3, and Comparative Example 1 are used to make button batteries and test them:

[0090] The prepared cathode material is composed of a conductive carbon black (Super P) as the active material, a conductive agent (polyvinylidene fluoride (PVDF) as the binder), and a mixture of the active material, Super P, and PVDF in a mass ratio of 7:2:1. N-methylpyrrolidone (NMP) is used as the solvent to form a slurry, which is then evenly coated on aluminum foil. The slurry is baked at 100°C for 1 hour, transferred to a vacuum drying oven, and dried at 80°C for 12 hours to obtain the positive electrode sheet. The negative electrode is sodium metal, the separator is a porous glass fiber membrane (GF / D), and the electrolyte is NaClO4 (1.0M NaClO4 in PC = 100 vol% with 50 vol% FEC).

[0091] Test conditions: electrochemical test was performed at a rate of 0.2C (1C = 130 mAh / g). The test results are shown in Table 1.

[0092] Table 1

[0093]

[0094]

[0095] Test results show that the use of composite materials significantly improves the Na3V2(PO4)2O2F material, with performance improvements becoming more pronounced as the composite content increases. The cycling performance of Na3V2(PO4)2O2F also improves under high pressure.

[0096] The above is a detailed introduction to a positive electrode composite material and preparation method, battery, and electrical device provided in the embodiments of the present application. Specific examples are used in this application to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solutions and core ideas of the present application; ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing a composite positive electrode material, characterized in that: The steps include: The first sodium source, the ferrous salt and the first phosphate are mixed and granulated, sintered and subjected to a first ball milling to obtain dawsonite; Chemically removing sodium from the dapoxite to obtain an intermediate phase FePO4; A second sodium source, a vanadium source, a second phosphate, a fluorine source, and a reducing agent are prepared into a solution, the solution is adjusted to a preset pH value, and a hydrothermal reaction is performed to synthesize a NASICON structure Na3V2(PO4)2O2F; The intermediate phase FePO4 and the NASICON structure Na3V2(PO4)2O2F are mixed and subjected to a second ball milling to obtain the composite positive electrode material; The vanadium source includes at least one of ammonium metavanadate, vanadium oxide or vanadium sulfate; The molar ratio of the first sodium source, the ferrous salt, and the first phosphate is (0.9-1.2):1:1; The molar ratio of the second sodium source, the vanadium source, the second phosphate, the fluorine source and the reducing agent is 3:2:2:(2-2.5):(2-2.2); The mass ratio of the intermediate phase FePO4 and the NASICON structure Na3V2(PO4)2O2F is (0.1-15):(85-99.9).

2. The method for preparing a composite positive electrode material according to claim 1, wherein: The first sodium source comprises at least one of sodium carbonate, sodium acetate, sodium hydrogen phosphate, sodium phosphate or sodium hydroxide; and / or, The ferrous salt includes at least one of ferrous sulfate, ferrous stearate, ferrous nitrate or ferrous chloride; and / or, The first phosphate comprises at least one of phosphoric acid, ammonium hydrogen phosphate or ammonium dihydrogen phosphate; and / or, The second sodium source comprises at least one of sodium carbonate, sodium acetate, sodium hydrogen phosphate, sodium phosphate or sodium hydroxide; and / or, The second phosphate comprises at least one of phosphoric acid, ammonium hydrogen phosphate or ammonium dihydrogen phosphate; and / or, The fluorine source comprises at least one of sodium fluoride or ammonium bifluoride; and / or, The reducing agent includes at least one of citric acid or ascorbic acid.

3. The method for preparing a composite positive electrode material according to claim 1, wherein: The median particle size D of the intermediate phase FePO4 50 0.1 to 2 μm; and / or The median particle size D of the NASICON structure Na3V2(PO4)2O2F 50 2~10μm.

4. The method for preparing a composite positive electrode material according to claim 1, wherein: The sintering temperature is 350-480° C. and the holding time is 4-8 hours; and / or, The first ball milling has a rotation speed of 600 to 1000 rpm and a ball milling time of 8 to 12 hours; and / or, The hydrothermal reaction temperature is 180-220° C., and the reaction time is 12-18 hours; and / or, The preset pH value is 6 to 7; and / or, The second ball milling has a rotation speed of 400 to 5000 rpm and a ball milling time of 2 to 4 hours.

5. The method for preparing a composite positive electrode material according to claim 1, wherein: The step of chemically removing sodium from the dapoxite further comprises: The dalphidite is dissolved in a solvent, and a desodiumizing agent is added to carry out a desodiumizing reaction.

6. The method for preparing a composite positive electrode material according to claim 5, characterized in that: The sodium removal agent includes at least one of sodium persulfate, sodium hypochlorite and tetrafluoroborate; and / or, The molar ratio of the dapoxite to the desodiumizing agent is (1.0-1.5):1; and / or, The desodium reaction time is 4 to 24 hours.

7. A composite positive electrode material, characterized in that The composite positive electrode material is prepared by the preparation method according to any one of claims 1 to 6, wherein the composite positive electrode material includes FePO4 and NASICON structure Na3V2(PO4)2O2F, and the mass ratio of the FePO4 and the NASICON structure Na3V2(PO4)2O2F is (0.1~15):(85~99.9).

8. A battery comprising a positive electrode plate, characterized in that: The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer disposed on the positive electrode current collector, and the positive electrode active material layer includes the composite positive electrode material as claimed in claim 7 or the composite positive electrode material prepared by the preparation method according to any one of claims 1 to 6.

9. An electrical device, characterized in that: Comprising the battery as claimed in claim 8.

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