Growing Nanostructured CuO on Copper Foil via Chemical Etching to Upgrade Metallic Lithium Anode

Metallic lithium is one of the most promising anode materials to build next generation electrochemical power sources such as Li-air, Li-sulfur, and solid-state lithium batteries. The implementation of rechargeable Li-based batteries is plagued by issues including dendrites, pulverization, and an unstable solid electrolyte interface (SEI). Herein, we report the use of nanostructured CuO in situ grown on commercial copper foil (CuO@Cu) via chemical etching as a Li-reservoir substrate to stabilize SEI formation and Li stripping/plating. The lithiophilic interconnected CuO layer enhances electrolyte wettability. Besides, a mechanically stable Li₂O- and LiF-rich SEI is generated on CuO@Cu during initial discharge, which permits dense and uniform lithium deposition upon subsequent cycling. Compared with bare Cu, the CuO@Cu electrode exhibits superior performance in terms of Coulombic efficiency, discharge/charge overpotentials, and cyclability. By pairing with the Li-CuO@Cu anodes, full cells with LiFePO₄ and LiNi_1/3Mn_1/3Co_1/3O₂ cathodes sustain 300 cycles with 98.8% capacity retention at 1 C and deliver a specific capacity of 80 mAh g^-1 at 10 C, respectively. This work would shed light on the design of advanced current collectors with SEI modulation to upgrade lithium anodes.