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

By coating lithium iron phosphate materials with graphene, the problem of low density caused by excessive carbon content is solved, high conductivity and high density are achieved, and the performance of lithium iron phosphate battery materials is significantly improved.

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

Application Number
CN201010537386.1
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2010-11-10
Publication Date
2011-04-13
Estimated Expiration
Not applicable · inactive patent

AI Technical Summary

Technical Problem

During the carbon coating process of existing lithium iron phosphate materials, the carbon content is too high, resulting in low material density, which affects the electrochemical performance, and high-temperature sintering can lead to excessively large grains and reduced discharge capacity.

Method used

Using graphene as the carbon material, a graphene-dispersed aqueous solution is prepared through hydrothermal differential layer peeling technology, which tightly coats the lithium iron phosphate particles, reducing the carbon content and increasing the material density. Combined with heat treatment, the graphene and the lithium iron phosphate are closely combined.

Benefits of technology

The carbon content was reduced to 0.8-1%, the conductivity was maintained, the tap density was increased to 1.8g/cm3, the 0.1C capacity reached 155mAh/g, and the compacted density was increased, significantly improving the overall performance of lithium iron phosphate materials.

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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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Citation Information

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