Mechanistic Correlation between Intrinsic Properties of Commercial Cu Current Collectors and Lithium Deposition Behavior

Lithium metal batteries (LMBs) are regarded as promising next-generation energy-storage systems; however, their practical application is hindered by unstable lithium deposition and severe interfacial side reactions. While extensive efforts have focused on electrolyte design and interfacial engineering, the role of commercial Cu current collectors, particularly their intrinsic structure mechanics characteristics remain largely overlooked. Herein, commercial Cu foils with distinct intrinsic properties are systematically investigated to elucidate how their mechanical–microstructural characteristics govern lithium nucleation and growth behavior. By establishing a direct correlation between intrinsic properties, Li deposition morphology, and electrochemical performance, we reveal that tensile properties, defect structures, and surface homogeneity collectively regulate the interfacial energy landscape, Li + flux distribution, and local current density. Among the investigated samples, the 8+ Cu foil achieves an optimal balance between mechanical strength, ductility, and structural uniformity, enabling reduced nucleation overpotential and uniform, dense lithium deposition with suppressed dendrite formation. Consequently, it delivers superior electrochemical performance, including symmetric-cell voltage hysteresis/polarization of 32.2 mV at 1 mA cm –2 and 1 mAh cm –2, stable symmetric-cell cycling over 800 h, and stable cycling for more than 100 cycles at 0.5 C in LiFePO4 full cells. This work demonstrates that optimizing the intrinsic mechanical-performance-related characteristics of commercial Cu current collectors offers a practical and scalable strategy for regulating lithium deposition and improving LMB stability.