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A kind of preparation method of lithium iron phosphate lithium ion battery cathode electrode

A lithium-ion battery, lithium iron phosphate technology, applied in battery electrodes, secondary batteries, circuits, etc., can solve the problems of poor rate performance, low specific energy of lithium iron phosphate, poor conductivity, etc., to improve electrochemical performance, Effect of improving charge and discharge performance and preventing crystal growth

Active Publication Date: 2018-10-12
HUAZHONG AGRI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Among various electrode materials for lithium-ion batteries, lithium iron phosphate is one of the most promising cathode materials for lithium-ion batteries due to its excellent stability, environmental friendliness and low cost, but its poor conductivity has always restricted its development.
At present, the main problems that prevent lithium iron phosphate from becoming the cathode material of lithium-ion batteries for electric vehicles are its low specific energy and poor rate performance, which are mainly caused by the following two reasons: (1) Electronic conductivity of lithium iron phosphate (2) The diffusion coefficient of lithium ions in the lithium iron phosphate lattice is low, which restricts its rate performance, resulting in the poor performance of lithium iron phosphate lower specific energy

Method used

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  • A kind of preparation method of lithium iron phosphate lithium ion battery cathode electrode
  • A kind of preparation method of lithium iron phosphate lithium ion battery cathode electrode
  • A kind of preparation method of lithium iron phosphate lithium ion battery cathode electrode

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Effect test

Embodiment 1

[0023] 1) The lithium source Li 2 CO 3 , iron source FeC 2 o 4 2H 2 O, phosphorus source (NH 4 ) 2 HPO 4 Weigh and mix with a molar ratio of 1:2:2, ball mill with absolute ethanol as the medium at a speed of 600 rpm for 6 hours, and then transfer to an oven at 60°C for drying to obtain a lithium iron phosphate precursor ;

[0024] 2) Weigh the polybenzoxazine according to 20% of the mass of the lithium iron phosphate precursor, mix it with the lithium iron phosphate precursor, and use absolute ethanol as the medium to ball mill for 6 hours at a speed of 600 rpm, transfer Dried in an oven at 60°C to obtain a solid powder;

[0025] 3) placing the solid powder in a tube furnace, and calcining at 650° C. for 10 hours under an argon atmosphere to obtain a lithium iron phosphate lithium ion battery positive electrode material;

[0026] 4) Mix the obtained positive electrode material of lithium iron phosphate lithium ion battery with acetylene black and polyvinylidene fluori...

Embodiment 2

[0028] 1) The lithium source Li 2 CO 3 , iron source FeC 2 o 4 2H 2 O, phosphorus source (NH 4 ) 2 HPO 4 Weigh and mix at a molar ratio of 1:1:1, ball mill for 10 hours at a speed of 500 rpm with absolute ethanol as the medium, and then transfer to an oven at 50°C for drying to obtain a lithium iron phosphate precursor ;

[0029] 2) Weigh the polybenzoxazine according to 10% of the mass of the lithium iron phosphate precursor, mix it with the lithium iron phosphate precursor, and use absolute ethanol as the medium to ball mill for 10 hours at a speed of 500 rpm, transfer Dried in an oven at 50°C to obtain a solid powder;

[0030] 3) placing the solid powder in a tube furnace, and calcining at 550° C. for 15 hours under an argon atmosphere to obtain a lithium iron phosphate lithium ion battery positive electrode material;

[0031] 4) Mix the obtained positive electrode material of lithium iron phosphate lithium ion battery with acetylene black and polyvinylidene fluori...

Embodiment 3

[0033] 1) The lithium source Li 2 CO 3 , iron source FeC 2 o4 2H 2 O, phosphorus source (NH 4 ) 2 HPO 4 Weigh and mix with a molar ratio of 1:3:3, ball mill for 5 hours with absolute ethanol as the medium at a speed of 1000 rpm, and then transfer to an oven at 70°C for drying to obtain a lithium iron phosphate precursor ;

[0034] 2) Weigh the polybenzoxazine according to 30% of the mass of the lithium iron phosphate precursor, mix it with the lithium iron phosphate precursor, and use absolute ethanol as the medium to ball mill for 5 hours at a speed of 1000 rpm, transfer Dried in an oven at 70°C to obtain a solid powder;

[0035] 3) placing the solid powder in a tube furnace, and calcining at 800° C. for 5 hours under an argon atmosphere to obtain a lithium iron phosphate lithium ion battery positive electrode material;

[0036] 4) Mix the obtained positive electrode material of lithium iron phosphate lithium ion battery with acetylene black and polyvinylidene fluorid...

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Abstract

The invention discloses a preparation method of a lithium iron phosphate positive electrode of a lithium-ion battery. According to the method, a polybenzoxazine high-polymer material is utilized as a carbon source and a nitrogen source; lithium carbonate, ferrous oxalate and diammonium hydrogen phosphate are taken as raw materials; and a lithium iron phosphate positive electrode material of the lithium-ion battery is synthesized through ball-milling and high-temperature solid-phase reaction methods. By polybenzoxazine, a nitrogen-doped carbon coating layer is provided; the conductivity of the material is improved; carbon generated in the pyrolysis process after polybenzoxazine coating covers the surface of lithium iron phosphate; growth of crystal is effectively blocked; and the nanoscale material is formed, so that a diffusion path of a lithium ion is reduced; and the charge-discharge performance at high rate is improved.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, and in particular relates to a method for preparing a positive electrode of a lithium iron phosphate lithium ion battery. Background technique [0002] As an efficient energy conversion and storage system, lithium-ion power batteries have many advantages such as high energy density, high power density, high energy conversion efficiency, environmental friendliness, long service life and high safety, and have become ideal energy storage devices in the 21st century. With the increasing application of lithium-ion batteries, the performance requirements of lithium-ion batteries in various fields are also getting higher and higher. Obviously, traditional lithium-ion battery electrode materials can no longer fully meet the urgent needs of the development of electric vehicles. It is of great economic significance to develop lithium-ion battery electrode materials with higher energy density, better ra...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/1397H01M4/36H01M4/58H01M4/62H01M10/0525
CPCH01M4/1397H01M4/366H01M4/5825H01M4/625H01M4/628H01M10/0525Y02E60/10
Inventor 曹菲菲汪萍
Owner HUAZHONG AGRI UNIV