Electrolyte-Controlled Stripping Behavior of Electroplated Lithium Toward Efficient Lithium Metal Anodes

While extensive efforts have focused on mitigating non-uniform lithium deposition, lithium stripping-an equally critical process governing reversibility and Coulombic efficiency-remains poorly understood, particularly in relation to electrolyte chemistry. Here, we demonstrate that lithium stripping behavior is governed by the time-dependent evolution of the solid-electrolyte interphase (SEI), which varies systematically across electrolyte systems. Using correlative scanning electron microscopy and cryogenic transmission electron microscopy, we reveal that different electrolytes generate distinct spatial distributions of SEI thickness along lithium dendrites, leading to fundamentally different stripping pathways. Electrolytes exhibiting slow interfacial resistance growth form spatially homogeneous SEI shells and enable uniform lithium stripping, whereas electrolytes with rapid SEI growth develop pronounced SEI heterogeneity, inducing preferential stripping near the current collector. Extending this analysis across six representative electrolyte systems, we identify a strong correlation between the SEI thickness distribution, interfacial resistance growth rate, and stripping behavior. These findings establish a physicochemical framework linking electrolyte-dependent SEI evolution to lithium stripping dynamics and provide design principles for optimizing operating protocols to maximize lithium metal reversibility.