Enabling multi-cation electrolyte usage in LMBs for lower cost and operating temperature

Abstract

Alloy anodes form a promising path to the use of multi-cation electrolytes by increasing chemical stability. In this study, a lithium-magnesium alloy anode was developed such that lower cost and lower melting temperature multi-cation electrolytes could be incorporated in liquid metal batteries (LMBs). In a first part of this work, Lithium-magnesium was proven to be a viable anode in a standard uni-cation (Li+) Li-Mg/LiCl-LiF-LiI/Sb-Pb battery. SEM and EDS confirmed the stability of this anode with respect to the cathode (Sb-Pb) and the standard uni-cation electrolyte. Performance metrics (voltage, efficiencies, etc.) for the Li-Mg anode cell were found to be comparable to the analogous pure Li anode system. In a second part of this work, using the alloyed Li-Mg anode, we demonstrated successful cycling of cells using multi cation electrolytes in Li-Mg/LiBr-KBr/Sb-Pb and Li-Mg/LiCl-KCl/Sb-Pb LMBs. Each of these multi-cation electrolyte systems boasted an active materials energy cost of (<150$/kWh), which is less expensive than the metric cost to implement storage batteries in the electrical grid.[1] These results open the door to incorporating lower cost and lower melting temperature electrolyte candidates in LMBs by using alloyed anodes.