Intermediate-temperature liquid-solid metal battery by adopting Li4Ti5O12-based material as cathode

Liquid metal battery (LMB) is a promising candidate for grid energy storage due to its long cycle life, low cost and easy scale-up. However, it has some drawbacks like low cell voltage and high operating temperature. In this work, we used the solid lithium titanate (Li 4 Ti 5 O 12 ) instead of the liquid alloy as the cathode to promote the cell voltage and decrease the operating temperature. This liquid-solid metal battery was able to work at 350 °C by applying liquid lithium as anode, Li 4 Ti 5 O 12 -based material as cathode and LiCl-LiBr-KBr molten salt as electrolyte. The acquired Li | LiCl-LiBr-KBr | Li 4 Ti 5 O 12 @C Cu battery cycled at 1 C rate (3.61 mA cm −2 ) for over 100 cycles with 0.02% capacity decay per cycle. An overall energy efficiency of 80%, coulombic efficiency of 96%, 1.2 V discharge voltage and cathode utilization of 82% were obtained. Furthermore, the effects of the electronic conductivity of Li 4 Ti 5 O 12 -based materials, temperature and current density on the electrochemical performance of the cell were investigated.