Preparation method of surface-coating anode material of lithium ion battery

Abstract

The invention discloses a preparation method of a surface-coating anode material of a lithium ion battery. The preparation method comprises the steps of (1) mixing lithium iron phosphate, lithium nickel cobalt oxide, magnesium nitrate and cobalt oxide to form an anode material mixture, heating the anode material mixture to above the melting point of the magnesium nitrate, and cooling the mixture after reaction lasts for 2h to 6h; (2) grinding the cooled anode material mixture, sieving the ground anode material mixture by utilizing a 200-mesh screen, placing the sieved mixture into a mixing drying kettle, and spraying a lithium hydroxide saturated solution into the mixing drying kettle; (3) staring a mixer, spraying aluminum sulfate into the mixing drying kettle to obtain hydrolysis reaction mixture; (4) drying, thermally treating and cooling the hydrolysis reaction mixture, pulverizing the mixture, and sieving the mixture by utilizing the 200-mesh screen to obtain the surface-coating lithium ion battery anode material. The anode material prepared by adopting the preparation method is uniformly coated, so that the circulation stability is good, the quality is high, the specific capacity is high, when the anode material is applied to a lithium ion battery, t he capacity is high, the circulating stability is good, and the service life is long.

Description

technical field [0001] The invention relates to the field of battery preparation, in particular to a method for preparing a positive electrode material coated on the surface of a lithium ion 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. Currently used lithium-ion battery 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 g...

AI Technical Summary

Problems solved by technology

Currently used lithium-ion battery 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.