Lithium iron phosphate composite material and preparation method thereof

Abstract

The invention discloses a preparation method of a lithium iron phosphate composite material. The preparation method comprises the steps that a carbon gel-graphene precursor with a porous structure isprepared by raw materials of oxidized graphene, melamine, hydrogen peroxide, resorcinol and formaldehyde, a lithium iron phosphate anode material is coated with carbon gel, gas dopant is combined to be used for performing gas doping so as to obtain the high-capacity lithium iron phosphate composite material. The prepared lithium iron phosphate composite material has the advantages that the porousstructure of the carbon gel is adopted to enable a gas doping addition agent to be absorbed to a pore structure of lithium iron phosphate, and the specific capacity of the lithium iron phosphate composite material is improved; the carbon gel is adopted to coat the lithium iron phosphate anode material, the problems that the tap density is lower and the ion diffusion of the material is slow are solved, thereby improving the rate performance and tap density of the lithium iron phosphate composite material.

Description

technical field [0001] The invention relates to the technical field of lithium ion battery materials, in particular to a method for preparing a lithium iron phosphate composite material, and the lithium iron phosphate composite material obtained by the preparation method. Background technique [0002] At present, when energy is depleted and environmental pollution is becoming more and more serious, people's demand for green and efficient energy is becoming increasingly urgent. Lithium-ion batteries have become a powerful Advantageous new energy is the focus of current research. At present, lithium-ion batteries used in the field of electric vehicles mainly include lithium iron phosphate batteries and ternary batteries. Lithium iron phosphate batteries have become the most promising lithium batteries due to their stable structure, abundant resources, high safety performance, long cycle life, and good low-temperature performance. One of the ion battery materials, but due to t...

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Problems solved by technology

The doping technology often increases the gram capacity by doping metal elements, such as titanium compounds, manganese compounds, etc. Chinese patent CN103618083A discloses a production method for high-capacity and high-pressure lithium iron phosphate cathode materials, which mainly uses titanium doping , magnesium, and manganese crystals are integrated into the crystal structure of lithium iron phosphate, and the gram capacity and compaction density of the material are improved by coating and sintering. However, since the doping of metal elements is achieved by solid-phase grinding with a sand mill, there are uneven doping, Problems such as poor consistency limit the effect of doping technology on improving the energy density of lithium iron phosphate materials

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