Lithium-rich manganese-based ternary composite precursor, positive electrode material and preparation method of positive electrode material

Abstract

The invention discloses a lithium-rich manganese-based ternary composite precursor, a positive electrode material and a preparation method of the positive electrode material, and the positive electrode material is spherical or sphere-like particles, is formed by compounding three layers of materials, and comprises an inner core, a transition layer and a shell. The preparation method of the positive electrode material comprises the following steps: mixing a first nickel salt, a first cobalt salt, a first manganese salt, a first aluminum salt and an M2 salt to obtain a first metal liquid; second nickel salt, second cobalt salt, second manganese salt, second aluminum salt and M3 salt are mixed to obtain second molten metal; the first molten metal and the second molten metal are mixed to form third molten metal; carrying out a first mixing reaction to obtain a manganese-rich hydroxide core; forming a transition layer outside the inner core through a second mixing reaction; forming a ternary hydroxide shell outside the transition layer through a third mixing reaction to obtain a precursor; and mixing the precursor with a lithium source, and sintering to obtain the positive electrode material. The lithium ion diffusivity of the whole material can be remarkably improved, and the thermal stability, the first efficiency, the cycle performance and the rate capability of the material are remarkably improved.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a lithium-rich manganese-based@ternary composite precursor, a positive electrode material and a preparation method for the positive electrode material. Background technique [0002] The discharge specific capacity of lithium-rich manganese-based positive electrode materials is as high as 300mAh / g, which is about twice the specific discharge capacity of positive electrode materials such as lithium iron phosphate and ternary materials that have been commercially used at present, and is very suitable for a new generation of high energy density power Lithium battery cathode material. Lithium-rich manganese-based materials have the advantages of low cost, high capacity, non-toxic and safe. The specific discharge capacity of lithium-rich manganese-based cathode materials has an absolute advantage, but there is still a long way to go before it can be applied to power batt...

AI Technical Summary

Problems solved by technology

This is because when first charged above 4.5V, the O in the lattice 2- with Li + With Li 2 In order to maintain the balance of charge, the transition metal ions on the surface will migrate to the bulk phase and occupy the octahedral sites left by Li+, which will lead to the inability of Li+ to be completely reintercalated during discharge, resulting in irreversible capacity loss.

[0003]Second, the material is prone to continuous voltage decay during the electrochemical cycle, resulting in a continuous decline in its energy density, which seriously restricts large-scale applications

Images