Liquid metal batteries (LMBs), with long life, low cost, and high safety, are promising large-scale energy storage technology to achieve better utilization of intermittent renewable energy. However, there is often a trade-off between the energy density and rate capability in LMBs with binary alloy positive electrode. The poor rate capability is still an impediment to meet the demand for practical applications. Herein, in virtue of various electromotive force of Te, Sb, Bi alloying with Li, we propose a strategy of operando formation of Li₂Te with multi-channel structure on the surface of positive electrode. Such structure of positive electrode benefits ion transport during cycling and leads to the better rate capability. The achieved Li || Sb-Bi-Te_s5 (the subscript ‘s’ stands for ‘structure’, which means that Te is only for operando formation of multi-structure and doesn't provide cell capacity) cell exhibits superior rate performance with the capacity retention of 84.4% and energy density of 143 Wh kg⁻¹ at 1000 mA cm⁻² while they are only 43.8% and 76.56 Wh kg⁻¹ in the Li || Sb-Bi cell. This facile strategy can provide guidance for design of novel electrode materials with benign energy density and rate capability for LMBs.

Link:Operando formation of multi-channel positive electrode achieved via tellurium alloying in liquid metal battery - ScienceDirect