In Situ Formation of Nitrogen‐Rich Solid Electrolyte Interphase and Simultaneous Regulating Solvation Structures for Advanced Zn Metal Batteries

Abstract Zn metal as one of promising anode materials for aqueous batteries suffers from notorious dendrite growth, serious Zn corrosion and hydrogen evolution. Here, a bifunctional electrolyte additive, N‐methyl pyrrolidone (NMP), is developed to improve the electrochemical performance of Zn anode. NMP not only alters the solvation structure of Zn 2+ , but also in situ produces a dense N‐rich solid‐electrolyte‐interphase layer on Zn foils. This layer protects Zn foils from corrosive electrolytes and benefits the uniform plating/stripping of Zn. Hence, the asymmetrical cells with NMP in the electrolyte retain a high coulombic efficiency of 99.8 % over 1000 cycles. The symmetric cells survive ≈200 h for 10 mAh cm −2 at a high Zn utilization of 85.6 %. The full cells of Zn||MnO 2 show an impressive cumulative capacity even with lean electrolyte (E/C ratio=10 μL mAh −1 ), limited Zn supply (N/P ratio=2.3) and high areal capacity (5.0 mAh cm −2 ).