Method for preparing lithium iron phosphate serving as positive active material of lithium battery

A positive electrode active material, lithium iron phosphate technology, applied in the direction of battery electrodes, circuits, electrical components, etc., can solve the problems of large drying shrinkage, difficulty in industrial production, and high price of metal alkoxides, to achieve fine grain size and improve conductivity , the effect of controllable ingredients

Inactive Publication Date: 2010-08-25
SICHUAN NON FERROUS METALLURGY RES
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AI Technical Summary

Problems solved by technology

However, the usual sol-gel method precursor synthesis cycle is long, drying shrinkage is large, it is difficult to be used in industrial production
Some patents also use metal alkoxides as raw materials, but metal alkoxides are usually expensive, and their solvents are highly toxic, which has adverse effects on the environment

Method used

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  • Method for preparing lithium iron phosphate serving as positive active material of lithium battery
  • Method for preparing lithium iron phosphate serving as positive active material of lithium battery
  • Method for preparing lithium iron phosphate serving as positive active material of lithium battery

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preparation example Construction

[0029] A method for preparing lithium iron phosphate, a cathode active material of a lithium battery according to the present invention, the steps of the preparation process include:

[0030] 1. The lithium source, the iron source and the phosphorus source are formulated into a solution according to the molar ratio of 1-1.1:1:1, and the total concentration of metal ions in the solution is controlled at 0.5-2 mol / L.

[0031] 2. Add citric acid or ammonium citrate to the solution prepared in the first step, (at the same time, add doping metal source and organic carbon source as needed) keep the liquid temperature at 70-90°C in a water bath, and stir to concentrate the sol.

[0032] 3. After the sol is concentrated until the concentration of metal ions reaches 1.5-6mol / L, the sol is directly fed into the preheated to 650-750°C with a non-oxidizing atmosphere (can be pure nitrogen, pure argon, hydrogen containing 5-20%) Initiate self-propagating combustion reaction in the heater o...

Embodiment 1

[0040] Lithium-ion battery cathode material LIFePO4 preparation method

[0041] 1. Fe(NO3) 3 .9H 2 O 82.45g, Li 2 CO 3 7.46g, H 3 PO 4 23.06g (Li:Fe:P=1:1:1), weighed with a 500g electronic balance (precision 0.01g), put it into a 500ml glass beaker, add 200ml of deionized water, and stir until completely dissolved.

[0042] 2. Add 21g of C6H8O7.H2O and stir until completely dissolved.

[0043] 3. Stir and concentrate the above liquid in a water bath at a temperature of 75-85°C until its volume is reduced to 100ml.

[0044] 4. After the above-mentioned concentrated liquid is transferred to a ceramic beaker, it is placed in a stainless steel tube protected by a nitrogen flow in a tubular resistance furnace and preheated to 750°C. Incubate under these conditions for 5 minutes.

[0045] 5. After the time is up, the ceramic dish is sent to the cooling section, where it is cooled to room temperature (nitrogen is passed through the entire stainless steel tube).

[0046] 6. ...

Embodiment 2

[0048] Preparation method of LIFePO4 / C composite powder for positive electrode material of lithium ion battery

[0049] 1. Fe(NO3) 3 .9H 2 O 82.45g, Li 2 CO 3 7.83g, H 3 PO 4 23.06g (Li:Fe:P=1:1.05:1), weighed with a 500g electronic balance (precision 0.01g), put it into a 500ml glass beaker, add 200ml of deionized water, and stir until completely dissolved.

[0050] 2. Add 21g of C6H8O7.H2O and stir until completely dissolved. In addition, add 2.5 g of pre-dissolved methyl cellulose.

[0051] 3. In a water bath at a temperature of 75-85°C, stir and concentrate the above liquid until its volume is reduced to 100ml.

[0052] 4. After the above-mentioned concentrated liquid is transferred to a ceramic beaker, it is placed in a stainless steel tube protected by a nitrogen flow in a tubular resistance furnace and preheated to 750°C. Incubate under these conditions for 15 minutes.

[0053] 5. After the specified time is reached, the ceramic dish is sent to the cooling sect...

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Abstract

The invention discloses a method for preparing lithium iron phosphate serving as a positive active material of a lithium battery, and relates to a method for preparing lithium iron phosphate serving as a positive active material of a high-power lithium ion secondary battery by adopting a sol self-propagation method. The method is characterized by comprising the following preparation processes: manufacturing sol by using soluble iron salt, lithium salt, phosphoric acid, complexing agent and doped metal source and carbon source precursors as raw materials, concentrating the sol, and then initiating self-propagation combustion at the temperature of between 650 and 750 DEG C to synthesize olivine-type pure lithium iron phosphate, doped lithium iron phosphate or composite powder of carbon and one of the olivine-type pure lithium iron phosphate and the doped lithium iron phosphate. By using the method of the invention, the self-propagation combustion is directly initiated at the background temperature of between 650 and 750 DEG C in the non-oxidizing atmosphere without a gel process, so high-performance lithium iron phosphate powder with controllable components, uniformity and fine grains in 3 to 60 minutes can be obtained, wherein the lithium iron phosphate powder can be used as the high-quality positive material of the secondary lithium battery. The method can be used for batch production.

Description

technical field [0001] The invention discloses a preparation method of lithium iron phosphate, a cathode active material of a lithium battery, and relates to a method for preparing lithium iron phosphate, a cathode active material of a high-power lithium-ion secondary battery, by a sol self-propagating method. Background technique [0002] Research and development of new energy is an important basis for the sustainable development of human society. With the development of human society, people's demand for efficient, environmentally friendly and economical new energy is becoming stronger and stronger. As one of the important chemical power sources, lithium-ion batteries can be widely used in energy storage equipment, electric tools, light electric vehicles, electric locomotives, electric bicycles, small equipment, other small electrical appliances, miner's lamps, starting power supplies, stationary power supplies, military equipment and many other industries. In particular,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/1397H01M4/58
CPCY02E60/122Y02E60/10
Inventor 冯再张继忠岳波
Owner SICHUAN NON FERROUS METALLURGY RES
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