Method of preparing aluminum-substituted alfa-nickel hydroxide coated with beta-nickel hydroxide

Abstract

The invention discloses a method of preparing aluminum-substituted alfa-nickel hydroxide coated with beta-nickel hydroxide. The method comprises the steps of: dissolving nickel salt and aluminum salt in a 5:1 molar ratio of nickel to aluminum by using distilled water to prepare a mixture liquid; dissolving potassium hydroxide or sodium hydroxide in the distilled water to prepare alkaline solution of sodium hydroxide or potassium hydroxide; dropwise adding the alkaline solution into the mixture liquid, controlling a pH value, reacting, perform extraction filtration, washing, and drying to obtain aluminum-substituted alfa-nickel hydroxide powder; mixing aluminum-substituted alfa-nickel hydroxide with nickel ions, perform ultrasonic dispersion, dropwise adding the alkaline solution into the nickel salt solution which contains the aluminum-substituted alfa-nickel hydroxide, controlling the pH value, reacting, perform extraction filtration, washing, and drying to obtain the aluminum-substituted alfa-nickel hydroxide coated with the beta-nickel hydroxide. The method is simple in process and easy to control, the cost of raw materials is low, and the utilization rate and cycle performance of the aluminum-substituted alfa-nickel hydroxide coated with the beta-nickel hydroxide serving as an anode material active substance of a nickel-metal hydride battery are excellent.

Description

technical field [0001] The present invention relates to a kind of preparation method of battery material, particularly relate to alkaline nickel-based secondary battery, such as the positive electrode material nickel hydroxide (Ni(OH) 2 ) method of preparation. Background technique [0002] Nickel-hydrogen batteries are considered to be the preferred power batteries for electric vehicles due to their excellent comprehensive characteristics such as good safety, high energy density, low price and environmental friendliness. In a nickel-hydrogen battery, the performance of the positive active material is the key to improving the overall performance of the battery. Especially as a power battery for electric vehicles, the specific capacity of the nickel electrode needs to be further improved. At present, β-nickel hydroxide is widely used as the positive electrode active material of nickel-hydrogen batteries. After years of development, its actual electrochemical capacity is clos...

AI Technical Summary

Problems solved by technology

However, α-nickel hydroxide is easily converted to β-nickel hydroxide in a strongly alkaline electrode process, and the electrochemical performance also deteriorates.

Partially replacing nickel ions with aluminum ions can produce relatively stable aluminum-substituted α-nickel hydroxide, but aluminum ions will dissolve from the lattice of α-nickel hydroxide during long-term charge-discharge cycles, prompting aluminum to replace α-hydrogen Nickel oxide gradually transforms into β-nickel hydroxide, which causes the electrode performance to decline sharply