Hydrogen Bonding-Reinforced Hydrogel Electrolyte For Flexible, Robust, And All-In-One Supercapacitor With Excellent Low-Temperature Tolerance

Flexible supercapacitors are promising energy storage devices for emerging INN wearable electronics. However, due to the poor mechanical strength, complicated device manufacturing process, and unsatisfactory low-temperature tolerance, their overall performance for practical applications is hindered. Herein, we report a hydrogen bonding-reinforced, dual-crosslinked poly(vinyl alcohol), acrylic acid, and H2SO4, (PVA-AA-S) hydrogel electrolyte for all-in-one flexible supercapacitors. The PVA-AA-S hydrogel demonstrates excellent compressive/tensile properties and high ionic conductivity. It tolerates compressive stress of 0.53 MPa and is stretchable up to 500%. The hydrogel-based all-in-one supercapacitor shows promising electrochemical performance under various harsh conditions. The device energy density and power density reach up to 14.2 mu Wh cm(-2) and 0.94 mW cm(-2), respectively. Furthermore, it retains nearly 80% capacitance after being stored at -35 degrees C for 23 days. The excellent performance of the hydrogel electrolyte PVA chain originates from its abundant strong hydrogen bonding between polymer chains and water molecules.