Full-Process Proton Management Unlocks Long-Life Aqueous Zinc-Metal Batteries

Uncontrolled proton activity in aqueous electrolytes triggers detrimental side reactions that compromise the stability of zinc (Zn) metal anodes. To address this challenge, we propose a full-process proton regulation strategy enabled by the unique β-1,4-glycosidic framework of chitosan oligosaccharide (COS). The rigid COS backbone effectively constrains proton generation and transport in the electrolyte, while its preferential interfacial adsorption constructs an ultrathin molecular barrier that inhibits proton consumption at the Zn surface. This dual-function molecular architecture synergistically realizes “generation-transport-consumption” proton regulation, thereby delivering exceptional electrochemical performance: long-term cycling stability over 8,000 h in Zn||Zn symmetric cells, an average Coulombic efficiency of 99.84% over 2,300 cycles in Zn||Cu cells, and superior cycling stability for more than 2,000 cycles at 2 A g^–1 in Zn||MnO₂ full cells. This work reveals glycosidic frameworks as a universal and transferable design principle for aqueous batteries, shifting electrolyte design from functional group-centric optimization to framework-enabled regulation toward sustainable, high-performance energy storage.