Method for preparing lithium iron phosphate/carbon composite material of lithium ion battery

A lithium-ion battery and lithium iron phosphate technology, applied in battery electrodes, secondary batteries, circuits, etc., can solve the problems of reducing the bulk density of lithium iron phosphate materials, low tap density, and affecting the compaction density of pole pieces, etc., to achieve High bulk density and compaction density, increased bulk density and compaction density, and stable product quality

CN102013477AInactive Publication Date: 2011-04-13HEBEI LITAO BATTERY MATERIAL
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2011-04-13
Estimated Expiration
Not applicable · inactive patent
Patent Text Reader

Abstract

The invention relates to a method for preparing a lithium iron phosphate / carbon composite material of a lithium ion battery, which belongs to the technical field of lithium ion batteries. The method for preparing the lithium iron phosphate / carbon composite material of the lithium ion battery comprises the following steps of: 1) preparing a suspending graphene-dispersed aqueous solution system, namely, crushing graphite to 1 to 5 microns, adding the crushed graphite into distilled water or purified water, adding 0.1 to 5 percent of surfactant, heating with stirring the mixed solution to 180 to 250 DEG C in a sealing way, performing stirring for 2 to 6 hours and reducing the temperature; 2) crushing lithium iron phosphate to the particle size of 1 to 5 microns, adding the crushed lithium iron phosphate into the distilled water or the purified water, adding with stirring 0.01 to 1 percent of coupling agent, performing uniform stirring, adding the graphene-dispersed aqueous solution, and performing stirring and filtration; and 3) vacuum-drying solid powder obtained by the filtration, and calcinating the dried solid powder for 2 to 12 hours to obtain the graphene-coated lithium iron phosphate cathode material. The method has the advantages of simple process, high material performance, high conductivity, high bulk density, high compacted density and the like.
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Description

Technical field

[0001] The invention belongs to the technical field of lithium ion batteries, and particularly relates to a method for preparing lithium iron phosphate / carbon composite materials for lithium ion batteries. Background technique

[0002] At present, the synthesis methods of lithium iron phosphate materials are mainly divided into solid phase method and liquid phase method. The solid-phase method mainly uses iron salt, lithium salt and phosphate to achieve the synthesis of lithium iron phosphate by sintering at high temperature. The liquid phase method is to dissolve soluble iron salt, lithium salt and phosphate in a solvent, use ion reaction to make lithium iron phosphate or its precursor, and then sinter it at high temperature to make a finished product. The solid-phase method has simple reaction, easy handling of raw materials and high yield, but the morphology of raw materials is not easy to control, and the tapped density and compacted density of the product ar...

Examples

Embodiment 1

[0025] The preparation method of lithium iron phosphate / carbon composite material of lithium ion battery firstly prepares a stable suspension graphene-water system. The concentration of graphene in the system is 1%. Firstly, the natural graphite is crushed to an average particle size of about 1 micron, then added to distilled water, 0.1% of the surfactant phenylenediamine is added, and the temperature is increased to 180°C under high-speed shearing and stirring. Stirring is continued for 6 hours under high temperature and high pressure, and the temperature is lowered to obtain a stable suspension graphene-water system.

[0026] The pure lithium iron phosphate is crushed to an average particle size of 1 micron, and purified water is added according to the ratio of lithium iron phosphate: water = 1:1. Under stirring, 0.01% by weight of the coupling agent γ-mercaptopropyltrimethoxysilane is added to enhance the adsorption capacity of the lithium iron phosphate material on graphene,...

Embodiment 2

[0028] The preparation method of lithium iron phosphate / carbon composite material of lithium ion battery firstly prepares a stable suspension graphene-water system. The concentration of graphene in the system is generally 10%. Firstly, the natural graphite is crushed to an average particle size of 5 microns, and then added to purified water, added with 5% polyvinylpyrrolidone as a surfactant, and sealed and heated to 250°C under high-speed shear stirring. Stirring was continued for 2 hours under high temperature and high pressure, and the temperature was lowered to obtain a stable suspension graphene-water system.

[0029] The pure lithium iron phosphate is crushed to an average particle size of 5 microns, and purified water is added according to the ratio of lithium iron phosphate: water = 1:10. Under stirring, add 1% by weight of the coupling agent methyl isobutyl ketoxime silane to enhance the adsorption capacity of the lithium iron phosphate material on graphene, and stir un...

Embodiment 3

[0031] The preparation method of lithium iron phosphate / carbon composite material of lithium ion battery firstly prepares a stable suspension graphene-water system. The concentration of graphene in the system is 2%. First, the natural graphite is crushed to an average particle size of 2 microns, and then added to purified water, and 1% of the surfactant alkylphenol polyoxyethylene ether is added. Under high-speed shearing and stirring, the temperature is sealed and heated to 200°C. Stirring is continued for 4 hours under high temperature and high pressure, and the temperature is lowered to obtain a stable suspension graphene-water system.

[0032] Crush the pure lithium iron phosphate to an average particle size of 3 microns, and add pure water according to the ratio of lithium iron phosphate: water = 1:5. Under stirring, add 0.1% by weight of the coupling agent vinyl triethoxy silane to enhance the adsorption capacity of the lithium iron phosphate material on graphene, and stir...