Anode material and preparation method thereof

Abstract

The invention discloses an anode material and a preparation method of the anode material. The preparation method of the anode material comprises the following steps: (1) dissolving fluorine-containing polymer in a solvent to form solution A, and dissolving metal salt in the same solvent to form a solution B; (2) mixing and stirring the solution A and the solution B uniformly, adding unmodified anode material powder in the obtained mixed solution, stirring, drying, and calcining at 300-750 DEG C to obtain a fluorine ion doped and metal fluoride clad anode material with treated polymer surface membrane. The cores of the anode material particles are doped with fluorine ions, and the surface of the anode material particle is modified by the metal fluoride layer and the polymer surface membrane. According to the preparation method of the anode material, fluorine ion doping, metal fluoride cladding and the polymer surface membrane treatment are carried out by one step and the synthetic efficiency is high, and the obtained anode material is suitable for use under high charge cut-off voltage and has high thermal stability.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, and more specifically, the invention relates to a positive electrode material and a preparation method thereof. Background technique [0002] Among the positive electrode materials of lithium-ion batteries, lithium-nickel-cobalt-manganese (NCM) ternary materials are favored due to their high capacity (up to 250mAh / g, 91% of theoretical capacity), excellent safety performance and low price. has received extensive attention from researchers. However, the poor cycle performance of this material at high temperature restricts its application and development. [0003] The latest research shows that the reasons for the poor cycle performance of NCM ternary materials at high temperatures mainly include the following aspects: 1) Under high charge cut-off voltage, a large amount of high-valence Ni, Co, and Mn oxidize the electrolyte, resulting in electrolyte breakdown. consumption and the enrichment ...

AI Technical Summary

Problems solved by technology

[0003] The latest research shows that the reasons for the poor cycle performance of NCM ternary materials at high temperatures mainly include the following aspects: 1) Under high charge cut-off voltage, a large amount of high-valence Ni, Co, and Mn oxidize the electrolyte, resulting in electrolyte breakdown. consumption and the enrichment of surface by-products, thereby accelerating the attenuation of the cycle; 2) a small amount of trivalent Mn, which is prone to disproportionation reaction and lead to the dissolution of Mn ions; 3) the corrosion of HF acid on the active material, resulting in 4) The polarization increases during the cycle, resulting in a rapid decline in capacity; 5) The mixing phenomenon of lithium and nickel during the sintering process will further increase during the cycle, so as to reduce the Coulombic efficiency of the material, and further lead to capacity fading during cycling; 6) Oxygen loss on the 104 surface of the crystal will also cause electrolyte oxidation and accelerate structural damage, resulting in a decrease in cycle capacity