Carbon-coated lithium vanadium fluorophosphate lithium ion battery positive electrode material and preparation method thereof

A technology of carbon-coated lithium vanadium phosphate and lithium vanadium phosphate, which is applied in the field of carbon-coated lithium vanadium phosphate lithium-ion battery cathode materials and its preparation, can solve the problem of low phase purity and particle size of lithium vanadium phosphate Uneven diameter distribution, poor electrochemical performance and other problems, to achieve excellent electrochemical performance, uniform distribution of element components, and low production cost

Active Publication Date: 2019-05-14
大连融科储能集团股份有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The purpose of the present invention is to solve the problems that it is difficult to prepare single-phase lithium vanadium phosphate and lithium vanadium phosphate due to the unreasonable preparation method of the current lithium vanadium phosphate, the phase purity of the lithium vanadium phosphate is not high, the p

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  • Carbon-coated lithium vanadium fluorophosphate lithium ion battery positive electrode material and preparation method thereof
  • Carbon-coated lithium vanadium fluorophosphate lithium ion battery positive electrode material and preparation method thereof
  • Carbon-coated lithium vanadium fluorophosphate lithium ion battery positive electrode material and preparation method thereof

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preparation example Construction

[0031] The invention discloses a method for preparing a positive electrode material of a carbon-coated vanadium phosphate lithium lithium ion battery, which comprises the following steps:

[0032] Step (1), take vanadium, the vanadium source that the molar ratio of phosphorus element is 0.95-1.05, phosphorus source and the carbon source (preferably 60-100%wt) that is metal vanadium total content 40-150%wt, under stirring condition Add vanadium source, phosphorus source and carbon source to water to form a homogeneous solution, control the vanadium concentration in the solution to 0.5-10mol / L, preferably 3-8mol / L, and continue stirring until a stable viscous solution or solid is formed; In the present invention, the molar ratio of vanadium to phosphorus is 0.95-1.05, and beyond this range, the crystal phase purity of the vanadium phosphate intermediate and lithium vanadium phosphate synthesized later cannot be guaranteed. The preferred molar ratio of vanadium to phosphorus is 1:...

Embodiment 1

[0043] This embodiment discloses a method for preparing a carbon-coated lithium vanadium phosphate lithium ion battery positive electrode material, comprising the following steps:

[0044] Add 165.9g of vanadium dioxide, 230.1g of ammonium dihydrogen phosphate, and 80g of glucose into 200mL aqueous solution in sequence, and mechanically stir at 90°C. After the solution forms a uniform dark green viscous liquid, transfer it to an oven at 80°C. After drying, the dried sample was pulverized and calcined at 850° C. for 6 hours under the protection of nitrogen. After cooling to room temperature, it was pulverized to obtain black vanadium phosphate. From XRD (such as figure 1 Shown) analysis shows that gained product is vanadium phosphate, and crystallinity is high, without its miscellaneous phase peak.

[0045] Analyze the element content of vanadium phosphate, mix vanadium phosphate and lithium fluoride at a ratio of 1:1 according to the vanadium content, and add 0.4% polytetrafl...

Embodiment 2

[0048] This embodiment discloses a method for preparing a carbon-coated lithium vanadium phosphate lithium ion battery positive electrode material, comprising the following steps:

[0049] Add 100g of ammonium metavanadate and 97.7g of concentrated phosphoric acid into 200mL of aqueous solution in turn, and mechanically stir at 70°C. After the solution forms a uniform dark red solution, add 50mL of sucrose solution with a concentration of 1.4g / L, and continue to stir until the The green viscous liquid solidifies quickly. The sample is taken out and transferred to an oven for drying at 80°C. Then the dried sample is pulverized and calcined at 800°C for 12 hours under the protection of nitrogen. After cooling to room temperature, it is pulverized to obtain black vanadium phosphate.

[0050] According to the vanadium content, vanadium phosphate and lithium fluoride were mixed at a lithium vanadium ratio of 1:1.05, and water was used as a solvent to obtain a lithium fluorovanadium ...

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Abstract

The invention provides a carbon-coated lithium vanadium fluorophosphate lithium ion battery positive electrode material and a preparation method thereof; the preparation method of the carbon-coated lithium vanadium fluorophosphate lithium ion battery positive electrode material comprises the following steps that a vanadium source, a phosphorus source and a carbon source are added into water to form a solution, and continuous stirring is carried out until a stable viscous solution is formed or rapid solidifying is performed; drying is performed on the viscous solution or the solid obtained in the last step, and heat treatment is performed in a non-oxidizing atmosphere, and then crushing and grinding are carried out to obtain the black carbon coated vanadium phosphate powder; mixing is carried out on the carbon-coated vanadium phosphate powder, lithium fluoride and a fluorine source to obtain precursor powder, and under the non-oxidizing atmosphere, sintering is carried out at 550-750 DEG C for 0.5-10h to obtain the carbon-coated lithium vanadium fluorophosphate material. The method is simple in process route, easy to operate, low in generating cost and capable of realizing large-scale production. The carbon-coated lithium vanadium fluorophosphate lithium ion battery positive electrode material prepared by the method is high in phase purity, uniform in particle sizes and excellent in electrochemical performance.

Description

technical field [0001] The invention relates to lithium-ion battery cathode material technology, in particular to a carbon-coated vanadium phosphate lithium lithium-ion battery cathode material and a preparation method thereof. Background technique [0002] LiVPO was first reported by J.Barker in 2003 4 Application research of F as cathode material for lithium-ion batteries. Lithium vanadium fluorophosphate (LiVPO 4 F) is a new type of polyanionic material, which belongs to the triclinic crystal system, and its structure is composed of PO4 tetrahedron and VO 4 f 2 The three-dimensional network structure constructed by octahedron, in which PO 4 Tetrahedron and VO 4 f 2 Octahedrons share one oxygen vertex, and VO 4 f 2 The octahedra are connected by fluorine vertices, and lithium ions occupy two different positions. As the cathode material, LiVPO 4 F inherits the advantages of safe cathode material for polyanion lithium-ion batteries, small structural changes during ...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/58H01M4/62H01M10/0525
CPCY02E60/10
Inventor 杜乃旭王璐唐雨微罗光鉴尚俊龙李茜
Owner 大连融科储能集团股份有限公司
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