Building Ultra-Stable and Low-Polarization Composite Zn Anode Interface via Hydrated Polyzwitterionic Electrolyte Construction

Aqueous zinc metal batteries are noted for their cost effectiveness, safety and environmental friendliness. However, the water-induced notorious issues such as continuous electrolyte decomposition and uneven Zn electrochemical deposition remarkably restrict the development of the long-life zinc metal batteries. In this study, zwitterionic sulfobetaine is introduced to copolymerize with acrylamide in zinc perchlorate (Zn(ClO4)(2)) solution. The designed gel framework with hydrophilic and charged groups can firmly anchor water molecules and construct ion migration channels to accelerate ion transport. The in situ generated hybrid interface, which is composed of the organic functionalized outer layer and inorganic Cl- containing inner layer, can synergically lower the mass transfer overpotential, reduce water-related side reactions and lead to uniform Zn deposition. Such a novel electrolyte configuration enables Zn//Zn cells with an ultra-long cycling life of over 3000 h and a low polarization potential (similar to 0.03 V) and Zn//Cu cells with high Coulombic efficiency of 99.18% for 1000 cycles. Full cells matched with MnO2 cathodes delivered laudable cycling stability and impressive shelving ability. Besides, the flexible quasi-solid-state batteries which are equipped with the anti-vandalism ability (such as cutting, hammering and soaking) can successfully power the LED simultaneously. Such a safe, processable and durable hydrogel promises significant application potential for long-life flexible electronic devices.

Automated summary

This study introduces a novel electrolyte configuration with zwitterionic sulfobetaine to address the issues in aqueous zinc metal batteries. The designed gel framework enhances ion transport, reduces mass transfer overpotential, and enables uniform zinc deposition. The results show that this electrolyte allows zinc metal batteries to achieve an ultra-long cycling life and high Coulombic efficiency, providing promising application potential for flexible electronic devices.