Decoding a Galvanic Corrosion-Driven Lithium Stripping Mechanism in Lithium-Free Anode Systems

Li-free lithium metal batteries (LFLMBs) increase cell-level energy density by eliminating excess lithium but remain sensitive to Coulombic efficiency (CE) losses. Here, we identify galvanic corrosion at the Li/Cu interface as an overlooked failure mechanism that distorts CE measurements and alters lithium stripping pathways, leading to inactive lithium accumulation. Using operando visualization, modeling, and DFT calculations, we show that corrosion-driven processes disrupt electronic connectivity and induce nonuniform stripping. We further demonstrate that maintaining percolating electronic pathways regulates lithium removal and reduces dead lithium formation. Because such conductive frameworks can be introduced through metallurgical or coating approaches, this work establishes a design principle for improving lithium reversibility in both Li-free and conventional lithium metal anodes.