Zn-Ion Transporting, In Situ Formed Robust Solid Electrolyte Interphase for Stable Zinc Metal Anodes over a Wide Temperature Range

Hydrogen evolution, corrosion, and dendrite formation in the Zn anodes limit their practical applications in aqueous Zn metal batteries. Herein, we propose an interfacial chemistry regulation strategy that uses hybrid electrolytes of water and a polar aprotic N,N-dimethylformamide to modify the Zn²⁺-solvation structure and in situ form a robust and Zn²⁺-conducting Zn₅(CO₃)₂(OH)₆ solid electrolyte interphase (SEI) on the Zn surface to achieve stable and dendrite-free Zn plating/stripping over a wide temperature range. As confirmed by ⁶⁷Zn nuclear magnetic resonance relaxometry, electrochemical characterizations, and molecular dynamics simulation, the electrochemically and thermally stable Zn₅(OH)₆(CO₃)₂-contained SEI achieved a high ionic conductivity of 0.04 to 1.27 mS cm^-1 from −30 to 70 °C and a thermally activated fast Zn²⁺ migration through the [010] plane. Consequently, extremely stable Zn-ion hybrid capacitors in hybrid electrolytes are demonstrated with high capacity retentions and Coulombic efficiencies over 14,000, 10,000, and 600 cycles at 25, −20, and 70 °C, respectively.