Hybrid Co-Solvent-Induced High-Entropy Electrolyte: Regulating of Hydrated Zn2+ Solvation Structures for Excellent Reversibility and Wide Temperature Adaptability

Abstract

As a new generation of lithium-ion battery alternative, aqueous zinc (Zn) ion batteries (ZIBs) garner tremendous interests for future energy storage application owing to their inherent incombustible, nontoxic, and low-cost features. However, their practical utilization is hampered by the electrolyte freezing at subzero conditions. In this study, a novel high-entropy (HE) electrolyte fabricated is presented with hybrid solvents to mitigate electrolyte freezing at low temperatures, restrain calendar corrosion, and boost Zn-ion transfer kinetics. Specifically, the isovolumetric combined ethyl acetate, ethylene glycol, and dimethyl sulfoxide as solvent components not only induce a reconfiguration of hydrogen bonding, but also alter the solvation sheath of Zn ions within the HE electrolyte environment. This synergistic coupling of hybrid co-solvents effectively harnesses the features of individual solvent additive and facilitates the remarkable advantages on cycling reversibility, especially in the low-temperature conditions. Benefiting from the anti-freezing and solvation structure regulation features, Zn symmetrical batteries equipped with HE electrolytes can work over 2500 h in low zinc salt concentration (1 m) at various temperatures. This work provides a facile modulation strategy to achieve the HE electrolyte, promoting the practical application and commercialization of advanced ZIBs with wide-temperature adaptability.