Small molecule-based supramolecular-polymer double-network hydrogel electrolytes for ultra-stretchable and waterproof Zn–air batteries working from −50 to 100 °C

Abstract

The continuing boom in the field of soft electronics has boosted the development of highly stretchable and environment-adaptable energy storage devices based on hydrogel electrolytes. Development of such soft energy supply devices still remains a challenging task since conventional hydrogel electrolytes are quite vulnerable to mechanical deformation and exhibit low temperature-tolerance to maintain their functions under extremely cold conditions. Herein, a small molecule-based supramolecular-polymer double-network (SP-DN) hydrogel platform was developed by introducing a series of non-covalent self-assembled guanosine G-quadruplex supramolecular networks into covalently cross-linked polyacrylamide polymer networks. The obtained KOH (6 M)-filled SP-DN hydrogels exhibited excellent stretchability (>1600%) and wide temperature-tolerance (from −196 to 100 °C), superior interfacial adhesion to various electrode substrates, and ultra-high low- and high-temperature conductivities (252.2 mS cm⁻¹ at −50 °C; 431.7 mS cm⁻¹ at 100 °C). All these outstanding properties strongly recommend the application of SP-DN hydrogels as quasi-solid electrolytes for highly stretchable (device-level elongation >1000%) and wearable Zn–air batteries (ZABs). More interestingly, without any special pre-treatment, the fabricated stretchable ZABs are highly waterproof and temperature-resistant (down to −50 °C and up to 100 °C) with a high energy/power density and a stable long-cycle life. This study offers a new option to design water-based hydrogel electrolytes for highly stretchable and environment-adaptable energy storage devices.