Enhancing the High-Temperature and High-Rate Properties of Nickel Hydroxide Electrode for Nickel-Based Secondary Batteries by Using Nanoscale Ca(OH)2 and γ-CoOOH

Abstract

Nanoscale Ca(OH)2 particles as a novel cathode additive for nickel-based secondary batteries are synthesized by a homogeneous precipitation method. The influence of Ca(OH)2 additive on the electrochemical performance of two types of nickel electrode (using spherical Ni(OH)2 and γ-CoOOH@Ni(OH)2) were evaluated. It is interestingly discovered that nano-Ca(OH)2 additives can efficiently improve the charge acceptance of both nickel electrodes. Especially, the charge acceptance of the 1.0 wt% nano-Ca(OH)2@γ-CoOOH@Ni(OH)2 electrode at 70°C at 5C is over 90% and the discharge capacity can reach about 218 mAh g−1. These performance enhancements of nickel electrode mainly result from the combined coating with Ca(OH)2 and γ-CoOOH. The modification of oxygen evolution reaction on the nickel electrode is primarily resulting from the use of Ca(OH)2 by increasing its potential and suppressing its rate. The observably lower charge transfer resistance of nickel electrode is mainly due to the high conductivity coating of γ-CoOOH. Consequently, the proposed cathode additive is promising for the high-temperature property enhancement of nickel-based rechargeable batteries.