Making method for positive material LiFePO4 of poly-aniline coated lithium ion battery

A technology for lithium ion batteries and positive electrode materials, which is applied in the field of preparation of positive electrode materials for lithium ion batteries, can solve the problems of poor high temperature cycle performance, low capacity, unsafe overcharge and impossible to use large-capacity batteries, etc., and achieves long cycle life. , The effect of high discharge capacity and high specific capacity

Inactive Publication Date: 2008-08-06
XIANGTAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the positive electrode materials used in lithium-ion batteries are mainly lithium-intercalated transition metal oxides, mainly using layered LiCoO 2 , the material has been widely used in small batteries, but in addition to the constraints of cobalt resources, the unsafe overcharge determines that it cannot be applied in large-capacity batteries
It is expected that spinel LiMn 2 o 4 Can rely on its cheap and relatively LiCoO 2 The advantages of safety play a role in large-capacity batteries, but a good solution has not been found for its shortcomings of low capacity and poor high-temperature cycle performance, so it still cannot be promoted in actual batteries
So far, there has been no literature report on the use of in-situ polymerization to coat polyaniline on the surface of lithium iron phosphate particles.

Method used

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  • Making method for positive material LiFePO4 of poly-aniline coated lithium ion battery
  • Making method for positive material LiFePO4 of poly-aniline coated lithium ion battery
  • Making method for positive material LiFePO4 of poly-aniline coated lithium ion battery

Examples

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Effect test

Embodiment 1

[0021] Accurately weigh Li according to the stoichiometric ratio 2 CO 3 , FeC 2 O 4 ·2H 2 O, (NH 4 ) 2 HPO 4 , Placed in a ball mill tank, the ratio of the size of the ball is 1:4, ball mill for 10 hours until the mixture is uniform. Then put the reactant in a quartz boat, put it into a tube furnace and heat up under the protection of argon. Firstly, the temperature is raised to 300°C at 5°C / min, the temperature is kept for 8h, and then it is naturally cooled to room temperature. After being taken out and ground, it is placed in a tube furnace again at 10°C / min to 700°C, kept for 20h and then naturally cooled to obtain LiFePO 4 . Weigh 4 grams of LiFePO 4 The powder was added to 0.1mol / L HCl and stirred for 30 minutes, 1mL aniline monomer was added and stirred for 30 minutes, 1.28g ammonium persulfate dissolved in 0.1mol / L HCl was added dropwise to the mixed solution, and the reaction was continued at room temperature. Stir under nitrogen protection. After reacting for 12 hours, s...

Embodiment 2

[0023] Accurately weigh Fe(NO 3 ) 3 ·9H 2 O, Li(CH 3 COO)·2H 2 O, dissolved in distilled water, add excess HOCH 2 COOH, will Fe 3+ Reduced to Fe 2+ , Then add the stoichiometric ratio of NH 4 H 2 PO 4 , Adjust the pH value to 8.5-9.2 with ammonia water, keep it at 60℃ for 24h to get the gel, heat the gel, protect it with argon, pre-decompose it at 300℃ for 3h, cool it and grind it into tablets. Calcined at 600℃ for 20h to obtain LiFePO 4 sample. Weigh 4 grams of LiFePO 4 The powder was added to 0.1mol / L HCl and stirred for 30 minutes, 1mL aniline monomer was added and stirred for 30 minutes, 1.28g ammonium persulfate dissolved in 0.1mol / L HCl was added dropwise to the monomer solution, and the reaction was carried out at room temperature. Stir continuously and protect with nitrogen. After reacting for 12 hours, stop stirring, filter and wash until the filtrate is colorless. Then, it was dried under vacuum at 60°C to obtain polyaniline-coated lithium iron phosphate. Using the lithi...

Embodiment 3

[0025] Prepare LiFePO under the same conditions as in Example 1. 4 . Weigh 4.5 grams of LiFePO 4The powder was added to 2mol / L HCl and stirred for 30 minutes, 0.5mL aniline monomer was added and stirred for 30 minutes, 0.64g ammonium persulfate dissolved in 2mol / L HCl was added dropwise to the monomer solution, and the reaction was continued at room temperature. Stir under nitrogen protection. After 6 hours of reaction, stop stirring, filter, and wash until the filtrate is colorless. Then, it was dried under vacuum at 60°C to obtain polyaniline-coated lithium iron phosphate. Using a lithium sheet as a negative electrode, the first specific discharge capacity of the polyaniline-coated lithium iron phosphate at room temperature was measured to be 133 mAh / g, and the capacity was still 110 mAh / g after 50 cycles of 1C.

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Abstract

The invention discloses a method for preparing polyaniline coating Li-ion battery anode material LiFePO4. The method is coating polyaniline on the in-situ surface of the powder of Li-ion battery anode material LiFePO4. The method has the following favorable effects: the discharging voltage platform of the polyaniline coating anode material LiFePO4obtained is stable, the battery has higher specific capacity up to one hundred and forty point three mAh/g, the granularity is distributed evenly, the grains are in good appearance and high in discharging capacity and long in cycling life, etc.

Description

Technical field [0001] The invention relates to a preparation method of a lithium ion battery cathode material. Background technique [0002] Lithium-ion batteries are a new generation of green high-energy batteries with excellent performance and have become one of the focuses of high-tech development. It stands out among many batteries for its high voltage, high capacity, low consumption, no memory effect, no pollution, small size, small internal resistance, less self-discharge, and more cycles. The application fields of lithium-ion batteries continue to expand. At present, their applications have penetrated into many civilian and military fields including telephones, notebook computers, video cameras, and digital cameras. In addition, domestic and foreign companies are also competing to develop large-capacity lithium-ion batteries for automobiles, aerospace, and energy storage. Cathode materials are an important part of lithium-ion batteries. At present, the cathode materials u...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/04B22F1/02C01B25/45H01M4/58H01M4/36
CPCY02E60/10
Inventor 雷钢铁易晓华陈效兰汪磊周姬李朝晖高德淑
Owner XIANGTAN UNIV
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