A kind of preparation method of potassium manganese doped lithium iron phosphate composite cathode material with high conductivity

Abstract

The invention relates to a preparation method of a potassium and manganese doped lithium iron phosphate composite anode material with high conductivity. The chemical formula of the multielement doped lithium iron phosphate composite anode material is Li(1-x)KxFe(1-y)MnyPO4, wherein x=0.15-0.3 and y=0.3-0.35. the preparation method comprises following steps: (1) a nano lithium iron phosphate precursor is prepared; and (2) acetylene black and polyethylene glycol are mixed, and the mixture is dispersed in ethanol by ultrasonic dispersion so as to obtain a conductive carbon dispersion liquid; the nano lithium iron phosphate precursor and the conductive carbon dispersion liquid are mixed, and the mixed solution is subjected to ball milling by a planetary ball mill; and the substances obtained after ball milling are dried, and are subjected to sintering in the presence of a reducing protective atmosphere so as to obtain the products. The potassium and manganese doped lithium iron phosphate composite anode material is used for lithium ion batteries; lithium iron phosphate is modified by doping of K and Mn, so that ion diffusivity is increased, generation of agglomeration is inhibited, and a conductive carbon-carbon network on the surface of lithium iron phosphate is formed.

Description

Technical field [0001] The invention relates to a preparation method of a high-conductivity potassium-manganese-doped lithium iron phosphate composite positive electrode material. Background technique [0002] With the rapid development of the battery industry, in order to solve many problems such as battery life, energy density, self-discharge or quality, various types of batteries have emerged. At present, due to the advantages of high energy density, long service life, light weight, and small self-discharge, lithium batteries have become the preferred power source for portable devices such as communication equipment and notebook computers, and have also begun to be applied to electric vehicles, national defense, etc. in large equipment. [0003] Lithium iron phosphate material is a cathode material for power lithium-ion batteries that has emerged in recent years and has been applied in large-scale industrialization. It has the property of intercalating and deintercalati...

AI Technical Summary

Problems solved by technology

The high-temperature solid-phase method is to roast lithium source compounds, iron source compounds, and phosphorus source compounds under the protection of an inert atmosphere to synthesize lithium iron phosphate; the advantage of the high-temperature solid-phase method is that the process is simple and easy to achieve industrialization, but the reactants are usually mixed unevenly. The product particles and grains are easy to grow, the purity is not high, the primary particle is too large, the migration path of lithium ions is too long, and the conductivity of lithium ions is poor, so the electrochemical performance is not good