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

Abstract

A narrow-distribution large-particle-size nickel-cobalt-aluminum hydroxide is divided into an inner layer and an outer layer, the inner layer is loose, the outer layer is tight, the specific surface area of the inner layer is 18-30 m<2> / g, and the overall specific surface area of precursor secondary spherical particles is 7-15 m<2> / g; crystal grains of the inner layer and the outer layer of the particles contain three elements of nickel, cobalt and aluminum, the inner layer of the precursor is of a loose structure with a large specific surface area, and when the precursor and a lithium sourceare used for sintering the positive electrode material, the lithium source can be rapidly and evenly diffused to an inner core, so the sintering efficiency of the positive electrode material is improved, and the production cost is reduced. The invention relates to a preparation method of the narrow-distribution large-particle-size nickel-cobalt-aluminum hydroxide. The preparation method overcomesthe defect that the precursor synthesized by a solid-phase method cannot reach the atomic-level uniformity on one hand, and also overcomes the defect of aluminum hydroxide flocculent precipitate generated in the conventional liquid-phase method synthesis process on the other hand, thereby obtaining the precursor with a double-layer structure with a loose inner layer and a compact outer layer.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion battery cathode material precursors, in particular to a narrow-distribution large-particle-diameter nickel-cobalt-aluminum hydroxide and a preparation method thereof. Background technique [0002] Nickel-cobalt-aluminum ternary cathode material (NCA, lithium nickel-cobalt aluminate) 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 and then sintered. However, this solid mixing method cannot achieve uniformity at the atomic level, and its performance is difficult to fully exert. [0004] Chinese patent CN108767256A di...

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Problems solved by technology

[0007] At the same time, with the increase of D50, during the sintering process of the positive electrode material, because the diffusion path of the lithium source from the outside of the precursor to the inside becomes longer, it becomes difficult to achieve a rapid and uniform distribution of the lithium source in the precursor, although it can This problem is solved by prolonging the sintering time or adopting multiple sintering methods, but it causes multiple problems such as decreased production efficiency and high production cost.

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