Method for preparing surface-coated anode material of lithium battery

Abstract

The invention discloses a method for preparing a surface-coated anode material of a lithium battery. The method comprises the steps of: mixing an anode material, namely lithium iron phosphate, with lithium nickel cobaltate, magnesium nitrate and cobalt oxide, heating an obtained mixture to the temperature above a melting point of the magnesium nitrate for reaction, and then cooling; performing ball milling for crushing, and sieving; placing a lithium hydroxide saturated solution in a spraying system, controlling the spraying system to spay in a mixing drying kettle, continuously starting a mixer, placing aluminum sulfate which is in exact complete reaction with the lithium hydroxide into the spraying system, controlling the spraying system to spray into the mixing and drying kettle, continuously mixing after spraying to complete hydrolysis reaction uniformly; drying a mixture obtained after hydrolysis reaction; and carrying out thermal treatment, crushing and sieving to obtain the surface-coated anode material of the lithium battery. The surface-coated anode material prepared according to the invention is uniform in coating and thus has good cyclic stability and high-quality specific capacity, and is high in capacity, good in cyclic stability and long in service when applied to the lithium ion battery.

Description

technical field [0001] The invention relates to a method for preparing a positive electrode material for a battery, in particular to a method for preparing a positive electrode material coated on the surface of a lithium battery. Background technique [0002] Due to its high energy density and good cycle performance, lithium-ion batteries have been widely used since their commercialization, gradually replacing traditional chemical power sources such as lead-acid batteries. [0003] The technical bottleneck of lithium-ion batteries mainly lies in the cathode material. Currently used, cathode materials have their own disadvantages: LiCoO 2 The price is high, the structure is unstable after the charging voltage exceeds 4.2V, and the safety becomes poor; LiNi 0.8 co 0.2 o 2 The cycle performance of LiNi is not good, the water absorption is strong, and the storage performance is poor; LiNi 0.8 co 0.15 Al 0.05 o 2 Easy to absorb water, poor storage performance; LiNi 1 / 3 c...

AI Technical Summary

Problems solved by technology

Currently used, cathode materials have their own disadvantages: LiCoO 2 The price is high, the structure is unstable after the charging voltage exceeds 4.2V, and the safety becomes poor; LiNi 0.8 co 0.2 o 2 The cycle performance of LiNi is not good, the water absorption is strong, and the storage performance is poor; LiNi 0.8 co 0.15 Al 0.05 o 2 Easy to absorb water, poor storage performance; LiNi 1 / 3 co 1 / 3 mn 1 / 3 o 2 The structure of LiMn is unstable, and the high temperature storage performance is not good; LiMn 2 o 4 The capacity is low and the high temperature performance is poor; LiFePO 4 Low electrical conductivity, poor low temperature performance

Both of the above two approaches have uneven coating, which leads to a decrease in the capacity and cycle performance of the coated positive electrode material, which shortens the battery life.