Method for preparing spherical nickel hydroxide with surface coated by gamma-hydroxy cobaltous oxide

Abstract

The invention provides a method for preparing spherical nickel hydroxide with the surface coated by gamma-hydroxy cobaltous oxide. The method comprises the steps of: firstly, preparing the spherical nickel hydroxide of which the surface is coated by cobaltous hydroxide, putting into a reactor, leading in oxygen under a stirring condition, pre-oxidizing until the color of a material inside the reactor stops changing, and controlling the temperature inside the reactor at 40-150 DEG C; adding an alkali metal hydroxide solution to the reactor; lastingly leading in oxygen under the stirring condition; and washing and baking an oxidized product by pure water after oxidizing reaction lasts for certain time, so as to obtain the spherical nickel hydroxide with the surface coated by the gama-hydroxy cobaltous oxide. By adopting the preparation method disclosed by the invention, a cobalt dissolved reaction at the initial stage of oxidization can be restrained; a lot of water is not generated in a preparation process; and the substances on a sieve when the materials are sieved are fewer.

Description

technical field [0001] The invention relates to a preparation method of a nickel battery material, in particular to a preparation method of spherical nickel hydroxide whose surface is coated with gamma cobalt oxyhydroxide. Background technique [0002] The positive electrode active material of the Ni-MH battery initially used conventional spherical nickel hydroxide. Since nickel hydroxide itself is a semiconductor, in high-power applications, its poor conductivity directly limits the high-current charge and discharge performance of the battery. In order to improve the conductivity of nickel hydroxide, people coated a layer of β-Co(OH) on the surface of spherical nickel hydroxide. 2 , developed a cobalt-coated nickel hydroxide positive electrode active material. This uniform coating of β-Co(OH) on the surface 2 Oxidation to generate β-CoOOH during charge and discharge can improve the uniformity of the conductive network, thereby improving the utilization of the nickel hydr...

AI Technical Summary

Problems solved by technology

[0004] However, in the preparation method described in the above-mentioned patent, the direct oxidation reaction of cobalt hydroxide will vary depending on the concentration of alkaline components present in the surroundings, the microscopic moisture of the particles, the temperature of the particles themselves during processing, the surrounding humidity and the concentration of oxygen, etc. There are large changes in different conditions, and there are complex reaction trajectories, so that the cobalt in part of the cobalt-coated layer will not be fully oxidized

Especially the generated water in the reaction process will cause the oxidized cobalt-coated spherical nickel to be easy to agglomerate. In the subsequent washing process, the cobalt-coated layer will be damaged due to adhesion, and the agglomeration will also cause more particles during sieving. Oversize