A kind of preparation method of lithium battery surface-coated positive electrode material

Abstract

The invention discloses a preparation method of a positive electrode material coated on the surface of a lithium battery: the positive electrode material lithium iron phosphate is mixed with lithium nickel cobaltate, magnesium nitrate, and cobalt oxide, and the obtained mixture is heated to above the melting point of magnesium nitrate for reaction. Cooling; ball milling, and sieving; place the saturated solution of lithium hydroxide in the spray system, control the spray system to spray the mixing and drying kettle, continue to start the mixer, and mix the aluminum sulfate whose content is just completely reacted with lithium hydroxide Put it in the spray system, control the spray system to spray the mixing and drying tank, continue mixing after spraying, so that the hydrolysis reaction can be completed evenly; dry the mixture after the hydrolysis reaction; heat treatment, crush and sieve to obtain surface coating treatment Lithium battery cathode material. The surface-coated cathode material prepared by the invention is evenly coated, so it has good cycle stability and high-quality specific capacity, and when used in lithium-ion batteries, it has high capacity, good cycle stability and long service life.

Description

Technical field [0001] The present invention involves a method of preparing a battery positive material, especially the preparation method of a lithium battery surface covering the positive pole material. Background technique [0002] Due to its high energy density and good circulation performance, lithium -ion batteries have been widely used since its commercialization, and gradually replaced traditional chemical power supply such as lead -acid batteries. [0003] The technical bottleneck of lithium -ion batteries is mainly the positive material.At present, the positive materials have their own shortcomings: 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 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 is unstable,...

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.