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

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 LiFePO₄ 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.