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

Abstract

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 SeSb 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.