Ultratough and recoverable ionogels based on multiple interpolymer hydrogen bonding as durable electrolytes for flexible solid-state supercapacitor

The emerging application of ionogels in flexible devices require it enough durable under repeated mechanical deformation while maintaining their superior electrochemical properties. In this work, ultratough and recoverable ionogels, where ionic liquids are confined in chemically and interpolymer hydrogen-bonding hybrid crosslinked network, were fabricated by in situ copolymerization of acrylic acid and 1-vinylimidazole monomer within 1-buty-3-methylimidazolium chloride ionic liquid. The reversible hydrogen bonds between imidazole and carboxylic acid groups of polymer chains in the network work as reversible “sacrificial bonds” to toughen ionogel, which makes the ionogels tough (tensile strength 1.62 MPa, toughness 8.7 MJ m⁻³), stretchable (elongation at break 1090%), and recoverable (91% recovery resting for 30 min, at 534 kPa stress and 500% strain). Moreover, the hydrogen-bonded ionogels exhibit high ionic conductivity of 2.3 S m⁻¹ at 80°C to 3.2 S m⁻¹ at 150°C. Furthermore, the ionogel-based flexible electrical double-layer capacitor can be operated up to 1.5 V with a capacitance of 341.47 F g⁻¹ at 0.5 A·g⁻¹ and exhibits excellent capacitance retention after 1000 cycles as well as superior electrochemical performance over a wide range of temperature. This work provides new insights into the synthesis of tough and recoverable ionogels for high-performance flexible supercapacitors.