Te-Cu dual adsorption-conversion function cathode enables high-energy-density and long-lifespan liquid metal batteries

Liquid metal batteries (LMBs) are an attractive large-scale energy storage technology due to their ultra-long service life, high safety, and exceptionally low comprehensive cost. Te-based LMBs are regarded as one of the most promising directions for developing high-energy-density LMBs. However, their practical application is still hindered by low Coulombic efficiency and short cycle life, primarily due to the shuttle effect induced by the dissolution of reaction products. Herein, the strategy of employing transition metal (Cu) with strong polar interactions with lithium polytellurides as the alloying element to construct cathode is proposed. Benefiting from the strong adsorption and conversion-promoting capabilities of in-situ generated metal tellurides (CuTe and Cu 4 Te 3 ) towards lithium polytellurides, the shuttle effect is significantly suppressed. The designed Li||Te 7 Cu 3 LMBs deliver a stable cycling performance of over 848 cycles with a coulombic efficiency exceeding 97%, ultrahigh energy density (465 Wh kg −1 ) and outstanding rate performance (2.1C, >90% capacity retention). This study opens up new avenues for designing high-performance Te-based LMB cathodes.