Ionic liquid-based electrolytes for aqueous zinc metal batteries

Aqueous zinc-metal batteries (AZMBs) are emerging as promising candidates for large-scale energy storage due to their intrinsic safety, low cost, and environmental friendliness. However, the practical application of AZMBs remains limited by persistent issues associated with the zinc anode, including dendrite formation, hydrogen evolution, corrosion, and surface passivation. Ionic liquids (ILs), with their unique physicochemical properties including wide electrochemical windows, low volatility, and high thermal stability, have demonstrated significant potential as electrolyte additives for stabilizing the zinc anode. This review systematically summarizes recent advances in ILs-based electrolytes for AZMBs, with a focus on the underlying mechanisms by which ILs regulate interfacial chemistry and electrochemical performance. We discuss the roles of ILs in modulating Zn²⁺ solvation structure, disrupting the hydrogen bond network of water, regulating interfacial thermodynamics and kinetics, and inducing the formation of robust solid-electrolyte interphase (SEI) layers. Moreover, the development of ILs-based gel electrolytes and polymeric ILs is highlighted for their enhanced mechanical stability and dendrite suppression capabilities. Finally, current challenges and future perspectives are outlined to guide the rational design and large-scale implementation of ILs-based electrolyte systems in next-generation AZMBs.