A Robust Hydrogel Electrolyte with Ultrahigh Ion Transference Number Derived from Zincophilic "Chain-Gear" Network Structure for Dendrite-Free Aqueous Zinc Ion Battery

As a promising energy storage device, an aqueous zinc ion battery (AZIB) still suffers dendrite growth, hydrogen evolution, and corrosion. Hydrogel electrolyte solves the above issues to some extent. Nevertheless, the mechanical properties of most hydrogel electrolytes are not competitive enough to meet booming demand for flexible electronics. In this work, a robust "chain-gear" hydrogel electrolyte (PM-HE) crosslinked by polymeric micelles (PMs) is constructed, in which PMs serve as "gears" and form "chain-gear" structure with polyanion chains. Specifically, "gears" support molecular chains, constructing hierarchically porous structures and opening up paths for Zn2+. Apart from as crosslinkers, PMs exist competitive mechanism with polyanion chains to promote ion decoupling. Such a "chain-gear" structure can realize desolvation and accelerate ion transport. Thereby, PM-HE possesses excellent ionic conductivity (60.6 mS cm-1) and ultrahigh transference number (0.88). Symmetrical cells can realize stable cycling over 1500 h with Zn uniform deposition. Remarkably, PM-HE has excellent tensile (0.23 MPa) and compressive (11.3 MPa) properties profited from strengthening and toughening effect of PMs. The flexible battery can supply power stably under harsh conditions. This work proposes the strategy of constructing an all-around hydrogel electrolyte based on reasonable design in network structure, providing more possibilities for the practical application of flexible AZIB. The hydrogel electrolyte with excellent mechanical and electrochemical properties is obtained by constructing a zincophilic "chain-gear" network, simultaneously realizing the rapid transport of zinc ions. In this way, the flexible battery which still works stably under external force is assembled. image