Non-sacrificial additive regulated electrode–electrolyte interface enables long-life, deeply rechargeable aqueous Zn anodes

Rechargeable aqueous Zn batteries (RAZBs) offer a promising solution for safe and cost-effective energy storage. However, practical applications of this type of battery are hindered by dendrite formation and side reactions, which primarily stem from the unstable Zn electrode–electrolyte interface (EEI). Here, we report 3-(1-pyridinio)-1-propanesulfonate (PPS) as a novel EEI regulator to tackle these critical issues. Theoretical calculations and experimental results reveal that PPS molecules can be preferentially adsorbed on the Zn anode surface and construct a lean-water EEI, which regulates uniform Zn plating/stripping and minimizes interfacial side reactions. As a result, the addition of PPS enables a Zn//Cu asymmetric cell to achieve an ultra-high Coulombic efficiency of 99.88 % and a lifespan of over 4,000 cycles (around half a year), far exceeding that with a conventional electrolyte (99.65 % and 210 cycles). Remarkably, even at 20 mA cm−2 and a high depth of discharge of 70 %, the Zn//Zn battery using the new electrolyte can still maintain an impressive cycling life of over 250 h. More importantly, the implementation of the designed electrolyte in various Zn-based full cells yields exceptional capacity retention and lifespan. This work underscores the importance of EEI regulation in advancing RAZB technology and offers a simple yet effective strategy for enhancing the stability and reversibility of Zn anodes, which represents a key step toward realizing the full potential of RAZBs for next-generation energy storage.