ZnNCN protective layer with high zincphilicity and ionic conductivity for stable zinc metal anodes

• ZnNCN layer shows high ionic conductivity (2.50 mS cm −1 ) and zincphilicity. • DFT calculations and experiments confirm the enhanced reaction kinetics in ZnNCN@Zn. • ZnNCN@Zn exhibits high durability and corrosion resistance during cycling. • COMSOL Multiphysics simulations reveal the uniform Zn deposition on ZnNCN@Zn. • ZnNCN@Zn shows superior electrochemical performance in both symmetric and full cells. Artificial solid electrolyte interphase (SEI) layers effectively address Zn dendrite formation and side reactions in zinc-ion batteries (ZIBs). However, the low ionic conductivities in conventional SEI layers often result in increased battery polarization voltages and reduced electrochemical performances in ZIBs. Herein, we report a highly zincophilic ZnNCN protective layer with superior ionic conductivity (2.50 mS cm −1 ) that enables a highly stable Zn anode with enhanced reaction kinetics. Compared to common ZnF 2 (0.90 mS cm −1 ) and Zn 3 (PO 4 ) 2 (1.71 mS cm −1 ) protective layers, the ZnNCN layer also exhibits lower Zn 2+ diffusion barriers (0.46 eV) and activation energy (17.28 kJ mol −1 ), which improves Zn 2+ deposition kinetics. Additionally, theoretical calculations reveal the strong binding energy between ZnNCN and hydrated Zn 2+ , which facilitates the Zn 2+ desolvation process. Consequently, ZnNCN@Zn symmetric cells achieve outstanding cycling stability of 2300 h at 0.5 mA cm −2 and 0.25 mA h cm −2 . Moreover, ZnNCN@Zn||MnOOH full batteries deliver an initial discharge capacity of 125 mA h g −1 at 0.5 A g −1 with nearly 100 % capacity retention after 500 cycles. This work provides valuable insights into developing high-stability ZIBs through high ionic conductivity artificial SEI layers.