Influence of electrolyte concentration on the electrochemical characteristics of LaGaO3 perovskite oxide as novel anode material for Ni/MH batteries

Recently, the ABO(3)-type perovskite oxides have been proposed as a promising novel anode for (Ni/MH) rechargeable battery due to the best electrochemical performances. In this work, LaGaO3 perovskite was synthesized by a sol-gel technique and their physico-chemical properties for Ni/MH batteries application are tested in details under various KOH electrolyte concentrations (1 M, 3 M and 7 M). The electrochemical measurements showed that all the electrochemical parameters, such as the activation cycle number, the maximum capacity (C-max), the hydrogen diffusion (D-H) and the exchange current density (I-0) have been greatly influenced by the variation of KOH concentration. It was found that with increasing electrolyte concentration, the activation process of this oxide was improved leading to an increase of the highest electrochemical capacity from 10 mAh g(-1) (1 M) to 220 mAh g(-1) (7 M). Also, the hydrogen diffusion and the current density increase with increasing KOH, which implies that increasing KOH concentration is beneficial to hydrogen diffusion process and charge transfer reaction. All the measurements revealed that the best electrochemical performances of the negative electrode are obtained at KOH 7 M.