Speaker
Description
Higher performance batteries are required for a sustainable society. Therefore, the development of lithium-air batteries (LAB) with high energy density is expected. As important chemical reactions in LAB, oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) occur during charge and discharge, respectively. Li+ reacts with O2 to produce Li2O2 during discharge while decomposition of Li2O2 occurs during charge1). However, Li2O2 is an insulating substance. Consequently, the formation of Li2O2 can lead to low cycle performance and low discharge capacity. To improve the performance of LAB, it is necessary to develop new catalyst materials for OER and ORR. According to previous studies, redox mediators (RMs) as soluble catalysts such as LiI, LiBr, and 2,5-di-tert-butyl-1,4-benzoquinone (DBBQ)1-3) have reduced overpotential or increased discharge capacity. Furthermore, it has been reported that metal oxides such as perovskite oxide and spinel oxide as solid catalyst materials could reduce charge overpotential1),4). In this study, we aimed to synthesized the composite materials composed of perovskite and spinel oxides. In addition, by using RM with ORR activity, we tried to improve cycle performance in LAB by the synergistic effect of the RM and the composite materials. The evaluation of the synthesized composite materials and the cycle performance of LABs using RM and the composite materials will be shown in the presentation.
