Synthesizing lithium ion cell positive material fluorophosphoric vanadium-lithium by sol-gel method

A technology of lithium-ion batteries and lithium vanadium phosphate, applied in battery electrodes, electrode manufacturing, circuits, etc., can solve the problems of uneven particle size distribution of synthetic materials, unfavorable industrial production, and low electrical conductivity, and achieve lower calcination temperature, The effect of shortening the synthesis cycle and uniform particle size distribution

Inactive Publication Date: 2007-07-25
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

For example, J Barker et al. reported a two-step synthesis method using carbothermal reduction. This method is cumbersome and complicated, which is not conducive to industrial production, and the particle size distribution of the synthesized material is uneven, the conductivity is low, the cycle is long, and the energy consumption is large.

Method used

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  • Synthesizing lithium ion cell positive material fluorophosphoric vanadium-lithium by sol-gel method
  • Synthesizing lithium ion cell positive material fluorophosphoric vanadium-lithium by sol-gel method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Fully dissolve 0.1mol vanadium pentoxide, 0.2mol ammonium dihydrogen phosphate, 0.2mol lithium hydroxide, 0.2mol ammonium fluoride, and 0.4mol oxalic acid, then stir and mix, then add 0.05-0.2mol sodium hydroxide to control the pH value 8. React in a stirred reactor at 40°C for 4 hours to form a gel. Send the gel sample into a vacuum drying oven for further drying at 100°C for 10 hours to obtain a dry gel. After completion, send the mixture into a tube furnace with temperature control, and heat it at 200°C for 3 hours to decompose the organic matter, and then cool it naturally with the furnace. Remove the sample and grind it carefully. Then the samples were sent to a tube furnace, and samples No. 1, 2, 3, and 4 were calcined at 450°C, 550°C, 650°C, and 750°C for 10 hours under the protection of an inert gas. The resulting No. 3 sample product was analyzed by X-ray diffraction, showing that it was all LiVPO 4 F, without any impurity phase, the particle size of the prod...

Embodiment 2

[0024] After fully stirring and mixing 0.2mol ammonium metavanadate, 0.2mol triammonium phosphate, 0.2mol lithium hydroxide, 0.2mol ammonium fluoride, and 0.4mol citric acid, add 0.05-0.2mol sodium hydroxide to control the pH value to 8. React in a stirred reactor at 50°C for 3h to form a gel. Send the gel sample into a vacuum drying oven for further drying at 120°C for 8 hours to obtain a dry gel. After completion, send the mixture into a tube furnace with temperature program control, and pretreat it at 300°C for 2 hours to decompose the organic matter, and cool it naturally with the furnace , take out the sample and grind it carefully. Then samples Nos. 1, 2, 3, and 4 were sent into a tube furnace, heated to 650° C. under the protection of an inert gas, and calcined for 5, 10, 15, and 20 hours, respectively. The resulting product was analyzed by X-ray diffraction, showing that they were all LiVPO 4 F, without any impurity phase, the particle size of the product obtained by...

Embodiment 3

[0027] Example 3 Mix 0.2mol lithium fluoride, 0.2mol ammonium metavanadate, 0.2mol ammonium dihydrogen phosphate, and 0.4mol citric acid, and stir evenly, adjust the pH value to 8, and react in a stirred reactor at 60°C 2h to form a gel. Send the gel sample into a vacuum drying oven for further drying at 150°C for 6 hours to obtain a dry gel. After completion, send the mixture into a tube furnace with temperature control, and pretreat it at 400°C for 1 hour to decompose the organic matter, and cool it naturally with the furnace , take out the sample and grind it carefully. Then samples Nos. 1, 2, 3, and 4 were sent into a tube furnace, heated to 400°C under the protection of an inert gas, and calcined for 5, 10, 15, and 20 hours, respectively. The resulting product was analyzed by X-ray diffraction, showing that they were all LiVPO 4 F, without any impurity phase, the particle size of the product obtained by SEM is about 100nm. The obtained product was assembled into an exp...

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Abstract

The disclosed sol gel method includes steps: stirring, and mixing objects: water solutions of lithium salt, villiaumite, vandic salt in pentavalence, phosphate, and chelating agent according to mol ratio 2í†2í†1-2í†2í†4; controlling pH at 7-11, carrying out reaction in stirred reactor under 40-80 deg.C for 1-5 hours to form gel; drying the gel in vacuum drying oven for 5-15h under 80-150 deg.C, and cracking the dried gel for 1-4h; after being ground evenly, the dried gel is roasted at 400-800 deg.C under atmosphere of inert gases for 5-20h so as to obtain finished product. Using vandic salt in pentavalence as raw material, the invention solves issue that vanadium ion is to be oxidized. The invention reduces burning temperature; producing fine and grain size even distributed material so as to raise conductivity. Adjustable synthesis temperature can obtain material with different granularities. Advantages are: simple and convenient method, and shortened synthetic cycle.

Description

technical field [0001] The invention relates to a method for synthesizing lithium vanadium vanadium phosphate, a cathode material of a lithium ion battery, by a sol-gel method. Background technique [0002] Lithium-ion batteries have many excellent characteristics and have been widely used in portable electronic products, communication tools, electric vehicles, and energy storage equipment. The performance of lithium-ion batteries depends largely on the cathode material. Among them, lithium vanadium fluorophosphate (LiVPO) in the vanadium-based cathode material 4 F) Due to its good reversible performance, rich sources of raw materials, high specific capacity (theoretical capacity is 156mAh / g), and high platform ratio (4.2V vs Li + / Li) and other advantages have attracted great attention. But the following disadvantages hinder its practical application: (1) V in synthesis 3+ easily oxidized to V 5+ , it is not easy to obtain single-phase LiVPO...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58H01M4/48H01M4/04C04B35/622C04B35/624C04B35/64C01D15/00C01B25/00C01B9/08C01B11/24C01G31/00
CPCY02E60/10
Inventor 张宝钟胜奎尹周澜
Owner CENT SOUTH UNIV
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