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 (Li₄Ti₅O₁₂) 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, Li₄Ti₅O₁₂-based material as cathode and LiCl-LiBr-KBr molten salt as electrolyte. The acquired Li | LiCl-LiBr-KBr | Li₄Ti₅O₁₂@C[sbnd]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 Li₄Ti₅O₁₂-based materials, temperature and current density on the electrochemical performance of the cell were investigated.