Preparation method of silicon-based lithium nickel phosphate composite material

Abstract

The invention relates to a preparation method of a silicon-based lithium nickel phosphate composite material and aims at solving the problem of poor charge and discharge performance of a lithium nickel phosphate material prepared by an existing method at a high rate. A manganese source compound, a doped compound and an ammonium phosphate compound (comprising monoammonium phosphate, diammonium hydrogen phosphate and triammonium phosphate) are mixed to prepare a precursor of which the molecular formula is SiNi<1-x>M<x>PO<4> in a superfine grinding manner; x is smaller than or equal to 0.2 and greater than or equal to 0; M is selected from one or more of Co, Fe, Mg and Ni; a dispersant is an organic solvent; the SiNi<1-x>M<x>PO<4> precursor and a lithium salt compound are mixed evenly and then transferred into a hydrothermal kettle, and are dried to obtain the lithium nickel phosphate material after reacting at a certain temperature for appropriate time; and finally the silicon-based lithium nickel phosphate composite material is prepared in a thermal treatment in-situ carbon-coating manner. The preparation method has the advantages of being simple in procedure and relatively low in cost; and the prepared silicon-based lithium nickel phosphate composite material has the advantages of relatively good charge and discharge performance and relatively good cycle performance.

Description

technical field [0001] The invention relates to a preparation method of a silicon-based lithium nickel phosphate composite material. Background technique [0002] Lithium-ion batteries are currently the most ideal power system for driving electric vehicles and hybrid vehicles. Compared with other lithium-ion battery cathode materials, lithium nickel phosphate has a higher theoretical capacity and discharge voltage platform, good safety and low cost, and is environmentally friendly. And other advantages, it is considered to be an ideal cathode material for automotive power batteries. However, the inherent ion diffusion rate and low electronic conductivity of nickel lithium phosphate materials also restrict its practical application. The current improvement measures mainly focus on the surface conductive carbon material coating of nickel lithium phosphate materials, which can improve to a certain extent. The conductivity of lithium nickel phosphate material is improved. [0...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to solve the problem that the existing lithium nickel phosphate material has poor charge and discharge performance at high rates. The present invention provides a preparation method of lithium nickel phosphate / carbon composite material