Electron Reconstruction at Heterointerface Enables Stable‐Fermi‐Level Lithium Metal Anodes

Abstract The practical implementation of lithium metal anodes (LMAs) requires precise regulation of Li deposition behavior and a stable electrode/electrolyte interface. However, stabilizing the interfacial Fermi‐level via electron redistribution is critical yet challenging for LMAs. In this work, a novel self‐supporting LMA host is designed, featuring a sea cucumber‐like carbon cloth anchored with Co/CoSe 2 heterostructure that achieves the simultaneous regulation of Li deposition dynamics and interfacial Fermi‐level stability. DFT calculations reveal that the Co/CoSe 2 heterointerface exhibits the highest binding energy toward Li, accelerating the de‐solvation and adsorption kinetics of Li + . Notably, the spontaneously formed built‐in electric field within the heterointerface induces interfacial electron redistribution, which crucially stabilizes the LMA's Fermi‐level to achieve uniform Li deposition. Moreover, this Fermi‐level anchoring effect exhibits the strongest affinity toward TFSI anions to promote the preferential decomposition to form a robust inorganic‐rich solid electrolyte interphase, thereby effectively reducing parasitic reactions by suppressing electron tunneling. As expected, when paired with high‐loading LiFePO 4 (20 mg cm −2 ), the full cells with a low negative/positive areal capacity ratio demonstrate 85.1% capacity retention after 500 cycles. Overall, this work establishes heterointerface‐mediated Fermi‐level engineering as a paradigm for breaking the energy efficiency‐lifespan trade‐off in metal batteries.