Improvement of High-Temperature Characteristics of the Sintered Nickel Positive Electrode for an Alkaline Storage Battery

Abstract

The high-temperature characteristics of sintered nickel positive electrodes for alkaline storage batteries such as nickel-metal hydride batteries and nickel-cadmium batteries were investigated. Generally, the discharge capacity of an alkaline storage battery charged at high temperature is smaller than that charged at room temperature due to the oxygen evolution reaction. In order to enhance high-temperature characteristics, we coated sintered nickel positive electrodes with yttrium hydroxide, calcium hydroxide or cobalt hydroxide. The high-temperature characteristics of the sintered nickel positive electrodes coated with yttrium hydroxide and calcium hydroxide by immersing them in sodium hydroxide solution after immersing in nitrate solution were greatly enhanced because of the increased oxygen overvoltage.