Helmholtz plane engineering for stable zinc anodes: from interfacial dynamics to long-cycle battery design

Abstract

Aqueous zinc-ion batteries (ZIBs) have emerged as promising candidates for large-scale energy storage systems due to their inherent safety, cost-effectiveness, and environmental compatibility. However, their practical implementation is significantly hindered by inadequate cycling stability, primarily attributed to the dynamic failure mechanisms of electrode/electrolyte interfacial layers. The Helmholtz plane at zinc anode interfaces serves as a pivotal regulator of interfacial electrochemistry, with its targeted modulation offering a strategic pathway to suppress zinc dendrite proliferation and parasitic hydrogen evolution. This review systematically dissects advanced Helmholtz plane engineering strategies, establishing their critical role in achieving long-term cycling stability for ZIBs. To address interfacial challenges at the zinc anode, this work comprehensively reviews advanced approaches for Helmholtz plane reconstruction, including the use of functional additives and the modification of artificial solid electrolyte interfaces. Special explanation is placed on how the desolvation process of zinc ions and the optimization of electric field distribution fundamentally reconstruct the Helmholtz plane, thereby effectively suppressing anode-side parasitic reactions. This review elucidates the underlying mechanisms of reconstructing the Helmholtz plane from the unique perspective of the structural characteristics of additives. It provides a practical reference for designing electrode materials and electrolyte interfaces for ZIBs with high-performance. Furthermore, this work serves as a significant guide for the study and reconstruction of the interface structure on the electrode of ZIBs.