Method for preparing lithium iron phosphate as lithium ion cell positive-pole material

A lithium ion battery, lithium iron phosphate technology, applied in electrode manufacturing, battery electrodes, chemical instruments and methods, etc., can solve the problems of complex surface compounding and large interface resistance, etc.

Active Publication Date: 2007-11-14
WUXI KAITIANXING PHOTOELECTRIC MATERIAL
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the surface recombination of elemental carbon and oxide is more complicated, and its interface resistance is relatively large. Lithium iron phosphate, as a composite oxide and carbon interface, has the same problem.

Method used

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  • Method for preparing lithium iron phosphate as lithium ion cell positive-pole material
  • Method for preparing lithium iron phosphate as lithium ion cell positive-pole material

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] A preparation method of lithium iron phosphate, a cathode material for lithium ion batteries, uniformly mixing lithium dihydrogen phosphate and ferrous oxalate, controlling the molar ratio of phosphorus, iron and lithium in the raw materials to be 1.0:1.0:1.0, using argon as a protective atmosphere , heating up to 530°C within 3 hours, keeping the temperature for 6 hours, and then cooling to room temperature to obtain a pure phase of lithium iron phosphate;

[0020] Add inorganic conductive and ultrafine carbon black and carbon-containing conductive agent precursor sucrose in the pure phase of lithium iron phosphate, the addition of carbon black is 5% of the weight of lithium iron phosphate, and the addition of sucrose is 5% of the weight of lithium iron phosphate , after fully mixing, heat treatment at 850°C for 15 minutes, and the output is the positive electrode material lithium iron phosphate. Fig. 1 is an X-ray diffraction pattern, and the obtained lithium iron pho...

Embodiment 2

[0024] A preparation method of lithium iron phosphate, a cathode material for lithium ion batteries, uniformly mixes ferrous oxide, lithium oxide, and phosphorus pentoxide, controls the molar ratio of phosphorus, iron, and lithium in the raw materials to be 1.0:0.85:1.00, and uses nitrogen as the In a protective atmosphere, heat up to 600°C within 5 hours, keep the temperature for 8 hours, and then cool to room temperature to obtain a pure phase of lithium iron phosphate;

[0025] Addition of conductive boride MgB in pure phase of lithium iron phosphate 2 and MoB 2 , MgB 2 The amount added is 15% of the weight of lithium iron phosphate, MoB 2 The added amount is 5% of the weight of lithium iron phosphate. After fully mixing, heat treatment at 800° C. for 1 hour, and the output is the positive electrode material lithium iron phosphate.

Embodiment 3

[0027] A preparation method of lithium iron phosphate, a cathode material for lithium ion batteries, uniformly mixes lithium phosphate and iron hydroxide, controls the molar ratio of phosphorus, iron and lithium in the raw materials to be 1.0:0.95:1.00, uses hydrogen and argon as a protective atmosphere, and Raise the temperature to 700°C within 6 hours, keep the temperature for 5 hours, and then cool to room temperature to obtain a pure phase of lithium iron phosphate;

[0028]In the pure phase of lithium iron phosphate, a composite conductive agent composed of conductive carbide TiC and carbon-containing conductive agent precursor gelatin and ethylene glycol is added. The addition of TiC is 1% of the weight of lithium iron phosphate, and the addition of gelatin is The weight of lithium is 2%, and the amount of ethylene glycol added is 8% of the weight of lithium iron phosphate. After fully mixing, heat treatment at 1000° C. for 0.1 hour, and the output is the positive electro...

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Abstract

It is a kind of preparation method of lithium iron phosphate which is an anode material of lithium ion battery, it adopts two-step technics: firstly, mix the following material such as iron, lithium and phosphate evenly and compound lithium iron phosphate of better crystal degree at lower temperature; then mix up lithium iron phosphate and composite conductive agent (inorganic conductive matter and precursor which is a carbon-contained conductive agent) sufficiently, it can get anode material of lithium ion battery which has a good electrochemistry capability through heat processing for short time at higher temperature, and the material has a good crystal performance and a strong interface function with conductive agent which makes material's conductivity of lithium ion and electron high, and it is suitable for charge / discharge of large rate. This technique's material is cheap chemical product, the composed techniques is simple, it is easy for large-scale production, the method to add conductive agent of electron is unique, electrochemistry capability of the products is of good performance.

Description

technical field [0001] The invention relates to a preparation method of a positive electrode material of a lithium ion battery, in particular to a method for preparing lithium iron phosphate, a positive electrode material of a lithium ion battery, by adopting a two-step process and a composite conductive agent. Background technique [0002] Lithium iron phosphate, as the positive electrode material for lithium-ion batteries, has good electrochemical performance, the charging and discharging platform is very stable, and the structure is stable during charging and discharging. At the same time, the material is non-toxic, non-polluting, and has good safety performance. The advantages of use and wide range of raw material sources are currently hot spots in the battery industry's development and research. [0003] The preparation methods of lithium iron phosphate mainly include high-temperature solid-state reaction method, liquid-phase co-deposition method, sol-gel method, etc. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/45H01M4/04H01M4/1397
CPCY02E60/10
Inventor 黄富坤黄富金黄敏黄强
Owner WUXI KAITIANXING PHOTOELECTRIC MATERIAL
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