N, O‐Codoped Carbon Nanosheet Array Enabling Stable Lithium Metal Anode

Abstract Lithium metal anodes hold great potential for next‐generation high‐energy batteries. However, the low Coulombic efficiency (CE) and dendritic growth during lithium metal plating/stripping cause short cycle life and deter its practical application. Herein, nitrogen, oxygen‐codoped vertical carbon nanosheet arrays are constructed on Cu foil (NOCA@Cu) as the efficient host to improve CE and suppress Li dendrites through polymer interfacial self‐assembly and morphology‐preserved pyrolysis. Benefitting from numerous vertical porous channels with abundant lithiophilic heteroatom dopants, 3D structured NOCA@Cu host can guide Li nucleation and growth in a controlled manner, leading to dendrite‐free Li deposition with high CE and long life cycles in both carbonate electrolyte and ether electrolyte, surpassing horizontal carbon‐coated Cu and pure Cu hosts. Finite element simulation further reveals the structural function of vertical carbon arrays as not only directing Li plating in the nanoarray‐constructed confined space but also homogenizing the distribution of ion concentration and electrical field throughout the 3D electrode. To demonstrate the practical application of lithiated NOCA@Cu anode, it is coupled with a commercial LiFePO 4 cathode, delivering high capacity and long‐cycle stability with nearly 100% CE. The cost‐effective, scalable, and efficient features render NOCA@Cu a promising Li host toward practical lithium metal batteries.