Long-Cycle Aqueous Zinc-Ion Batteries Enabled by Interfacial Engineering via Hydrogen-Bond Disruption and pH Stabilization

Abstract

Aqueous zinc-ion batteries (AZIBs) offer advantages such as safety, low cost, and environmental friendliness. However, challenges such as dendrite growth, hydrogen evolution reaction (HER), and byproduct formation, i.e., zinc hydroxide sulfate (ZHS), severely limit their cycling stability and practical application. In this work, diammonium hydrogen phosphate (DAP) is introduced as a multifunctional additive to simultaneously address these challenges through three synergistic mechanisms: (1) promoting the preferential deposition of Zn²⁺ along the (002) crystal plane, thereby inhibiting dendrite growth; (2) disrupting the hydrogen-bonding network in aqueous media to mitigate HER; and (3) buffering local pH fluctuations to prevent ZHS precipitation. Notably, the introduction of only 0.01 M DAP significantly extends the cycling lifespan of Zn||Zn symmetric cells to 5300 h at 5 mA cm^-2 and 0.5 mAh cm^-2. Moreover, the Zn||MnO₂ full cells achieve an exceptional capacity retention of 99.9% after 200 cycles at 1 A g^-1. These findings highlight the efficacy of trace DAP addition in enhancing the electrochemical stability of AZIBs and offer a promising strategy for the development of long-life aqueous zinc-based energy storage systems.