by Kun Wang, Sravani Duggirala, Jinghang Ji, Bhargav Bhamwala, Kun Ryu, Mingqian Li, Shen Wang, Kathryn Hicks, Wurigumula Bao and Ying Shirley Meng
Lithium metal anodes (LMAs) offer unrivaled theoretical capacity and the lowest electrochemical potentialamong practical anode materials, making them central to high energy density battery chemistries. Yet in most studies,the lithium foil itself is treated as a nominally interchangeable component, and the impact of its intrinsic variabilityon cell behavior remains poorly quantified. Here we systematically investigate how initial-state properties of com-mercial lithium foils influence electrochemical performance. Using a diverse sample set of 17 foils spanning manu-facturing routes, thicknesses, and storage histories, we quantify key bulk, surface, and microstructure descriptors. Byutilizing a combination of electrochemical measurements, surface optical and wetting characterization, and structuraland chemical analyses, we correlate initial state descriptors to plating/stripping behavior in Li||Cu cells and capacityretention in Li||NMC622 full cells. Our results reveal that lithium inventory, surface passivation state, and microstruc-ture each play distinct and complementary roles in governing cell performance. True lithium inventory primarilydictates the onset of lithium depletion. Optical lightness and electrolyte contact angle, which reflects the degreeof surface passivation, correlates with the overpotential in electrochemical process; microstructural features suchas grain size and texture influence stripping/plating homogeneity and the evolution of interfacial morphology.On this basis, we propose a practical workflow and set of screening criteria for lithium-foil quality assessment priorto cell assembly, combining simple, experimentally accessible metrics with targeted structural and chemical analysiswhen needed. The framework provides mechanistic insight into how variability in commercial lithium foils translatesinto cell-level behavior and offers actionable guidance for material selection, processing, and storage in lithium-metalbattery development.