High Performance Liquid Metal Battery with Environmentally Friendly Antimony–Tin Positive Electrode

For the first time, Sb–Sn alloys are reported as environmentally friendly positive electrodes for high performance liquid metal batteries (LMBs). Meanwhile, the dominant role of Sb in setting the potential and the inert “solvent” role of Sn in lowering the melting point and decreasing the cell cost are clarified on the basis of electrochemical titration and ex situ analysis. The Li||Sb–Sn LMB exhibits superior rate performance (only 13% capacity loss from 100 mA cm–2 to 1 A cm–2 of current densities), low materials cost (73 $ kW h–1), and high energy density (200.4 W h kg–1) at reduced operating temperature. Most notably, after 3500 h of operation (more than 430 full charge–discharge cycles), a discharge capacity of 20.6 Ah is maintained with a capacity retention of 96.7%, corresponding to a fade rate of 0.0078% per cycle, which potentially meets the metrics of large-scale energy storage without environmental concerns.