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

Abstract

Hydrogen evolution, corrosion, and dendrite for-mation 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 characteriza-tions, 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 degrees 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 degrees C, respectively.