Interfacial thermodynamic understanding of Zn anode failure via entropy-enthalpy competition.

Aqueous zinc-ion batteries (AZIBs) are promising candidates for large-scale energy storage owing to their safety, low cost, and material abundance. However, their practical deployment is hindered by interfacial failure of Zn metal anodes. While these issues have been widely investigated from kinetic, structural, and transport perspectives, the underlying thermodynamic driving forces remain less explored. This review re-examines the failure mechanisms of aqueous Zn metal anodes through the lens of interfacial thermodynamics. A fundamental thermodynamic asymmetry is proposed between the entropy-penalized Zn deposition and entropy-favored parasitic reactions including hydrogen evolution and corrosion. The structured electric double layer is further hypothesized to act as a low-entropy interfacial region that amplifies this imbalance. Re-evaluating prevailing stabilization strategies within this framework reveals their shared role in rebalancing the interfacial enthalpy-entropy landscape. This review aims to complement kinetic and structural analyses, offering a unified thermodynamic narrative to guide the design of more reversible Zn anodes.