Tellurium-tin based electrodes enabling liquid metal batteries for high specific energy storage applications

Abstract

Developing high energy density batteries is of great significance for various energy storage applications. The novel liquid metal batteries (LMBs), with the merits of low-cost and long-lifespan, however deliver relatively low specific energy due to the electromotive force (EMF) limitation of bimetallic electrodes. Metalloid tellurium (Te) is a potentially high voltage electrode candidate for LMB, but challenged by its poor electronic conductivity and high solubility in molten salts. Herein, for the first time, we demonstrate a high voltage LMB with high energy density enabled by metalloid Te alloying with metallic Sn as positive electrode. This Te-Sn alloying strategy dramatically enhances the electronic conductivity of Te based electrodes, and suppresses the solubility of Te in molten salt electrolyte as well. The Li||Te-Sn cells reported herein present the highest discharge voltage of ca.1.6 V and energy density of 495 Wh kg−1 among all the reported LMBs. These preliminary results broaden the selection of positive electrode materials for LMBs and demonstrate a strategy for developing high energy density batteries for energy storage applications.