Preparation method of high-nickel ternary material

Abstract

The invention provides a preparation method of a high-nickel ternary material. The high-nickel ternary material is Li<1+a>Ni<x>Co<y>M<z>O<2+b>, wherein a is greater than or equal to -0.10 and less than or equal to 0.50; x is greater than or equal to 0.8 and less than 0.9; y is greater than or equal to 0.1 and less than or equal to 0.25; z is greater than or equal to 0 and less than or equal to 0.25; b is greater than or equal to -0.05 and less than or equal to 0.10; M is at least one kind of Mn, Al, Ti, Ba, Sr, Mg, Cr, Zn, V and Cu; the preparation method comprises the steps of enabling a precursor and a lithium source to be mixed, and adding sintering auxiliaries to be mixed uniformly, and then performing sintering in a three-stage sintering mode, wherein the three-stage sintering mode iscarried out by performing sintering in the first stage, then performing sintering in the second stage and finally performing sintering in the third stage, and the sintering temperature in the secondstage is higher than that in the first stage and in the third stage. By adoption of the three-stage sintering mode, and by enabling the sintering temperature in the second stage to be higher than thatin the first stage and in the third stage, the prepared high-nickel ternary material is high in crystallinity and less in Li / Ni mixed arrangement, thereby realizing high structural stability, high initial efficiency and high power.

Description

technical field [0001] The application relates to the field of ternary materials, more specifically, the application relates to a method for preparing a high-nickel ternary material. Background technique [0002] As a new type of green energy, lithium-ion batteries have the advantages of high specific energy, small self-discharge, high open circuit voltage, no memory effect, long cycle life, and no environmental pollution, so they are widely used in mobile phones, notebook computers, digital cameras, etc. At the same time, lithium-ion batteries are also power sources for electric vehicles and energy storage power sources for solar renewable energy. [0003] The core link in the lithium-ion battery industry is the manufacture of battery materials. The performance of batteries depends to a large extent on the performance of cathode materials. Among them, nickel-cobalt-manganese or nickel-cobalt-aluminum ternary materials are the hotspots of the new generation of lithium-ion ca...

AI Technical Summary

Problems solved by technology

This sintering process is applicable to the preparation of nickel-cobalt-manganese or nickel-cobalt-aluminum ternary materials with low nickel content, but for nickel-cobalt-manganese or nickel-cobalt-aluminum ternary materials with nickel content > 80%, if this sintering method is used to obtain The performance of the material is poor, mainly due to: the crystallization window temperature of nickel-cobalt-manganese or nickel-cobalt-aluminum ternary materials is generally 750-800 ° C, if it is higher than this window temperature, it will lead to high content of tetravalent nickel in the surface layer of the material The ions lose oxygen atoms to form a spinel phase, resulting in oxygen defects, resulting in poor reversibility of the material; when sintering in the window temperature range, the low thermodynamic environment will cause the sintering of the material to be controlled by the kinetic speed, and it is necessary to The material is kept in this temperature range for more than 15 hours to improve the crystallinity of the material, and too long a holding time will greatly intensify the diffusion of Li ions to the transition metal layer, forming a high Li / Ni mixing phenomenon , leading to poor reversibility of the material

Due to the presence of oxygen vacancies and Li / Ni mixing, the prepared materials have poor structural stability, low first-time efficiency and low power.

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