A Dendritic Nickel Cobalt Sulfide Nanostructure for Alkaline Battery Electrodes

Abstract

A uniform dendritic NiCo2S4@NiCo2S4 hierarchical nanostructure of width ≈100 nm is successfully designed and synthesized. From kinetic analysis of the electrochemical reactions, those electrodes function in rechargeable alkaline batteries (RABs). The dendritic structure exhibited by the electrodes has a high discharge-specific capacity of 4.43 mAh cm−2 at a high current density of 240 mA cm−2 with a good rate capability of 70.1% after increasing the current densities from 40 to 240 mA cm−2. At low scan rate of 0.5 mV s−1 in cyclic voltammetry test, the semidiffusion controlled electrochemical reaction contributes ≈92% of the total capacity, this value decreases to ≈43% at a high scan rate of 20 mV s−1. These results enable a detailed analysis of the reaction mechanism for RABs and suggest design concepts for new electrode materials.