Synergistic Regulation of Interfacial pH and Desolvation Kinetics via a Zwitterionic Proton Reservoir for Durable Zinc Anodes

ABSTRACT The operational lifespan of metallic Zn anodes in aqueous Zn‐ion batteries (AZIBs) is fundamentally impeded by interfacial microenvironment instability, particularly the dynamic pH fluctuations that trigger severe corrosion and dendrite growth. Addressing this challenge, this work demonstrates a multifunctional electrolyte additive, 4‐(2‐hydroxyethyl)‐1‐piperazineethanesulfonic acid (HEPES), to reconstruct the anode interphase. Driven by a favorable LUMO energy level, HEPES preferentially chemisorbs within the inner Helmholtz plane of the Zn anode. Functionally, the piperazine moieties within HEPES serve as proton reservoirs to suppress hydrogen evolution, while simultaneously neutralizing interfacial alkalinity, thus dynamically stabilizing the local pH. Furthermore, the inherent Zn 2+ affinity of HEPES facilitates the desolvation of hydrated Zn 2+ and accelerates ion diffusion kinetics, reducing the nucleation overpotential for uniform Zn deposition. As a result, the optimized electrolyte endows the cells with ultra‐long cycling stability with reversible plating/stripping for 4500 h at 1 mA cm −2 and 1300 h at 10 mA cm −2 . Practical viability is further validated in full cells with a low N/P ratio (2.38:1), which retain 267.9 mAh g −1 over 500 cycles. This work not only resolves the pH‐induced interfacial instability, but also provides a new molecular electrolyte design strategy for enhancing redox kinetics in high‐performance AZIBs.