Ultraflexible, High-Strength All-in-One Supercapacitors With GO/PVA Xerogel Electrolyte for Completely Dry and Extremely Cold Environments

Flexible all-solid-state supercapacitors using liquid or hydrogel electrolytes face liquid leakage, volatilization, and freezing issues that disrupt ion conduction. This work pioneers a graphene oxide/polyvinyl alcohol (GO/PVA) xerogel electrolyte to overcome these challenges. The three-dimensional GO/PVA network features abundant hydrogen-bonded structures, enabling liquid-free proton conduction within this network. The device is fabricated via in situ growth of polyaniline on both sides of a GO/PVA hydrogel, followed by pressurized drying, which generates a well-integrated electrode–electrolyte interface. This monolithic structure facilitates proton transport via the Grotthuss mechanism. Under completely open conditions (no encapsulation), it retains 93.7% of initial capacitance after 768 h storage and 92.6% after 6 months. At 1 mA cm −2 (a fivefold increase from 0.2 mA cm −2 ), 98.5% capacitance is retained. Benefiting from its liquid-free nature, it achieves 715 mF cm −2 at 1 mA cm −2 and −30 °C after 6 months of storage under these open conditions, preserving 88.7% of its room-temperature capacitance. Pristine and boric acid-modified devices show tensile strengths of 2.8 MPa (221% strain) and 8.8 MPa (164% strain). Importantly, tensile behavior and flexibility remain unchanged even at −30 °C compared to room temperature, positioning this material as a promising candidate for flexible energy-storage devices operating in harsh environments. Graphical A flexible all-solid-state supercapacitor is developed using a GO/PVA xerogel electrolyte with a dense hydrogen-bonding network for liquid-free proton conduction via the Grotthuss mechanism. The in situ grown PANI electrodes and pressurized drying create a monolithic electrode–electrolyte interface. The device retains 92.6% capacitance after 6 months under open conditions and delivers 715 mF cm −2 at −30 °C, with unchanged flexibility.