Moderate hydrogen bond network via in-situ dissolved interfacial cation solvation for highly active aqueous zincmanganese batteries

Abstract

Aqueous zinc-manganese batteries (AZMBs) are regarded as strong contenders for next-generation energy storage systems due to their high safety and low cost.Considering the complex MnO2/Mn2+ deposition/dissolution mechanism, however, challenges arising from sluggish kinetics of such solid-liquid transition reaction. Hence, available interfacial H2O molecules with stable hydrogen bond networks exhibits its importance for fast proton transport and thus high interfacial reaction activity. Overactive H2O molecules construct short-lived hydrogen bond networks, and support fast but discontinuous proton hopping merely, while rigid H2O molecules configuration even cannot provide rational proton transfer path. Hence, this work proposed the synergistic effect between cationic solvation effect and solid-liquid electrolyte to constrain the in-situ dissolved cations at cathode interface to construct moderate and connective hydrogen bond networks by solvated H2O molecules. As a result, the K/Cu/MnO2 cathode with ZnMT-based electrolyte could provide the highest specific capacity of 360 mAh g-1 at 0.4 mA cm-2 , and remain high specific capacity of 450 mAh g-1 after rate performance. These findings pioneer new avenues in interface engineering, providing theoretical foundations for rational design of AZMBs with rapid kinetic responses.