A novel high voltage Se-Sb positive electrode material for high-energy-density liquid metal battery

Liquid metal battery (LMB) has gained significant notice in the field of large-scale energy storage due to their appealing cost-effectiveness, excellent cycle stability, and ultralong service lifetime. However, achieving high energy density in LMB still remains a significant challenge. Metalloid selenium (Se) is a competitively high voltage positive electrode candidate for LMB, but its application has been impeded by poor electronic conductivity and high solubility in molten salt electrolyte. Herein, we first demonstrate a high voltage LMB system with high energy density achieved by integrating metalloid Se alloyed with metallic antimony (Sb) as the positive electrode. The Se-Sb alloying strategy significantly improves the electronic conductivity of Se-based electrodes and effectively reduces the solubility of Se in the molten salt electrolyte. The lithium (Li)||Se-Sb cell presented in this study exhibits a remarkable discharge medium voltage of approximately 1.65 V and an impressive energy density of 346.2 Wh kg- 1 within 1.0-2.2 V, surpassing most of previously reported LMBs. These promising findings expand the range of positive electrode materials available for LMBs and create a novel avenue for high voltage liquid metal battery with enhanced energy density and stability.