Method for coating surface of nano-alpha-phase nickel hydroxide with CoOOH

Abstract

The invention discloses a method for coating the surface of nano-alpha-phase nickel hydroxide with CoOOH. The method is mainly characterized in that a precipitation conversion process is adopted to coat the surface of alpha-phase nickel hydroxide with a layer of CoOOH. The method obviously improves the conductive performance of the alpha-phase nickel hydroxide, and improves the electrode performance of nickel hydroxide, so the cell performances are obviously improved, for example, the specific capacity and the output power are improved, the large-rate discharge capability and the charge and discharge cycle performance are improved, and the oxygen evolution over-potential and the discharge plateau are improved. The discharge capacity of the cobalt coated nickel hydroxide prepared in the invention is high to 386mAh / g.

Description

(1) Technical field: [0001] The invention relates to the field of preparation of new chemical materials, in particular to a method for coating CoOOH on the surface of nano-α-phase nickel hydroxide. (two) background technology: [0002] α-phase nickel hydroxide is the positive electrode active material of alkaline rechargeable batteries such as nickel-hydrogen batteries. Compared with traditional spherical nickel (β-phase nickel hydroxide), it has a higher specific discharge capacity, no electrode expansion during discharge, and high-rate charging. The advantages of superior discharge performance have become one of the hot spots of nickel-metal hydride battery researchers in recent years. However, similar to the traditional spherical nickel, the conductivity of the α-phase nickel hydroxide material itself is relatively poor. In order to improve the utilization rate of the active material and its conductivity with the current collector, generally when making electrodes, the α-...

AI Technical Summary

Problems solved by technology

However, the plated nickel film will gradually oxidize to nickel hydroxide during the charge and discharge process and participate in the charge and discharge process of the battery, thereby destroying the conductive network formed by the conductive nickel film, resulting in a sharp decline in battery performance; The cobalt film on the surface will generate cobalt hydroxide and finally convert to CoOOH with high conductivity

However, from the perspective of the electroless plating process, its operating conditions are very harsh, and noble metals need to be used as catalysts, resulting in increased product costs and environmental pollution. Therefore, this process is limited in industrial production.

[0005] Similarly, cobalt hydroxide can be coated on the surface of α-phase nickel hydroxide by chemical methods, but the coated cobalt hydroxide must also be oxidized to highly conductive CoOOH to improve the electrode performance of the material, and the oxidation process itself is generally are slower and more complex