Definition of the aging process parameters for nickel hydroxide in the alkaline medium

Abstract

The parameters of the aging process of nickel hydroxide in the alkali medium, depending on aging time and presence of cobalt hydroxide additive, have been determined. It was revealed that the aging process is governed by re-crystallization of nickel hydroxide and it also occurs through the ordering of crystal lattice defects, including in the direction along (001) plane. It was determined that aging results in a significant decrease of the utilization coefficient of nickel hydroxide. It was also revealed that the aging rate is high initially, but decreases overtime. It was determined that the utilization coefficient for nickel hydroxide with and without cobalt hydroxide had decreased by 37 % and 47 %, respectively, after aging in 4.5M KOH for 56 days. The mechanism describing the change of the average discharge potential for the aged samples with cobalt hydroxide has been proposed. It is assumed that aging of nickel hydroxide with cobalt hydroxide leads to the formation of a layered double hydroxide film on the surface of nickel particles.