In situ construction of a stable composite solid electrolyte interphase for dendrite-free Zn batteries

Building a stable solid electrolyte interphase (SEI) has been regarded to be highly effective for mitigating the dendrite growth and parasitic side reactions of Zn anodes. Herein, a robust inorganic composite SEI layer is in situ constructed by introducing an organic cysteine additive to achieve long lifetime Zn metal batteries. The chemisorbed cysteine derivatives are electrochemically reduced to trigger a local alkaline environment for generating a gradient layered zinc hydroxide based multicomponent interphase. Such a unique interphase is of significant advantage as a corrosion inhibitor and Zn²⁺ modulator to enable reversible plating/stripping chemistry with a reduced desolvation energy barrier. Accordingly, the cells with a thin glass fiber separator (260 μm) deliver a prolonged lifespan beyond 2000 h and enhanced Coulombic efficiency of 99.5% over 450 cycles. This work will rationally elaborate in situ construction of a desirable SEI by implanting reductive additives for dendrite-free Zn anodes.