Narrow-distribution small-particle-size nickel-cobalt-aluminum hydroxide and preparation method thereof

Abstract

A narrow-distribution small-particle-size nickel-cobalt-aluminum hydroxide serves as a precursor of a nickel-cobalt-lithium aluminate battery positive electrode material active substance, an inner core of secondary spherical particles of the precursor is aluminum hydroxide, a crystal grain cation layer framework of an outer shell layer contains nickel-cobalt-aluminum elements, and the mole percentof nickel is 85-98%; and secondary spherical particles of the precursor have the characteristic of narrow distribution, K90 is (D90-D10) / D50 and is less than or equal to 0.90, D50 is 2.0-6.0 [mu]m, and the energy density and the cycle performance of the battery can be further improved when the secondary spherical particles are used as a positive electrode material of the lithium battery. The invention discloses a preparation method of the narrow-distribution small-particle-size nickel-cobalt-aluminum hydroxide. On one hand, the defect that a precursor synthesized by a solid phase method cannot achieve atomic-level uniformity is overcome, and on the other hand, aluminum hydroxide flocculent precipitate generated in the synthesis process of a conventional liquid phase method is also overcome, so that the precursor with a core-shell structure, good sphericity, compact particles, stable structure and high consistency is obtained.

Description

technical field [0001] The invention belongs to the technical field of positive electrode material precursors for lithium ion batteries, in particular to a narrow-distributed small particle size nickel-cobalt-aluminum hydroxide and a preparation method thereof. Background technique [0002] Nickel-cobalt-aluminum ternary cathode material (NCA, that is, nickel-cobalt-aluminum oxide lithium) has high energy density and good rate performance, and is widely used in power tools, electric vehicles and other fields. [0003] At present, the preparation methods of nickel-cobalt-aluminum materials mainly include solid-phase synthesis and liquid-phase synthesis. Solid-phase synthesis generally uses co-precipitation to prepare nickel-cobalt precursors, which are then mixed with aluminum compounds and lithium source compounds for sintering. [0004] Chinese patent CN108767256A discloses a method for preparing a lithium nickel cobalt aluminate precursor of a battery positive electrode m...

AI Technical Summary

Problems solved by technology

This preparation method is the above-mentioned solid-phase method, and the mixing method cannot achieve uniformity at the atomic level, and the effect is not ideal

[0005] The liquid-phase synthesis method is to prepare the precursor of nickel-cobalt-aluminum by chemical co-precipitation method, and then calcined with lithium salt to obtain NCA material; since the solubility product constant of aluminum hydroxide is 1.3×10 -33 , while nickel hydroxide and cobalt hydroxide (divalent) are 2×10 -15 and 1.6×10 -15 , the solubility product constant of aluminum hydroxide is much smaller than that of nickel hydroxide and cobalt hydroxide, and it is difficult for aluminum ions to undergo complexation reaction with ammonia water. The precipitation speed of aluminum ions is very fast, and it is easy to form flocculent products. Not only is it difficult to form a uniform single layered structure with nickel and cobalt precipitation, but it is also difficult to form spherical large particle precipitation. Unsatisfactory indicators, loose particles, poor structural stability and low discharge capacity

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