A dual lithiated alloy interphase layer for high-energy–density lithium metal batteries

The fluoropolymer and coordination compound with aluminum as the central atom are first designed to convert an organic/dual alloy of LixAl-LixP hybrid interphase layer, leading Li short-term storage and restraining the accumulation of inactive lithium as well as achieving long-term cycling life. [Display omitted] •Conversion mechanism of aluminum coordination compound at the interface of lithium metal anode.•Li short-term storage feature of dual lithiated alloy to improve charge redistribution.•Organic/dual alloy of LixAl-LixP hybrid interphase is designed to regulate Li deposition morphology.•Interface evolution analysis at different state of charge.•Long-term cycling performance of Li metal batteries. Lithium metal batteries represent potential candidates for high-energy–density batteries. However, non-uniform Li deposition and dendrite growth limit the practical applications of Li anodes in solid-state and liquid-phase battery systems. This report investigates the conversion mechanism of an aluminum coordination compound (Al(MMP)3) at the interface of a lithium metal anode. Based on the proposed mechanism, a novel dual alloy comprising a LixAl-LixP hybrid interphase is designed to promote interfacial charge balance. Under the synergic effect of a fluoropolymer, the organic/inorganic protective layer containing the dual lithiated alloy exhibits short-term Li storage and rapid Li+ transport, thereby limiting the accumulation of inactive lithium and decreasing the Li+ migration barrier. Upon implementing the hybrid anode, the electrochemical life span of the Li metal battery exceeds 2000 h. Moreover, pairing with a Ni-rich cathode leads to excellent capacity retention and stable coulomb efficiency. The developed strategy can guide future advancements in lithium metal batteries with long cycle lives.