Redox-active Quinone Cross-linked Gel Electrolytes Enabled High-performance Supercapacitors

The extremely limited energy density and leakage risks of liquid electrolytes in supercapacitors have hindered their widespread industrialization. In this study, a novel cross-linked gel polymer electrolyte was designed and prepared by incorporating redox-active units to enhance energy density and address leakage issues in supercapacitors. These quasi-solid-state redox-active electrolytes (DCBQ@PVA) were synthesized through nucleophilic functionalization of a polyvinyl alcohol (PVA) matrix with dichlorobenzoquinone (DCBQ) redox crosslinkers. Electrolyte membranes were fabricated via solution casting, and their performance was systematically optimized. As expected, the DCBQ@PVA gel electrolyte significantly improved the electrochemical performance of quasi-solid-state supercapacitors, expanding the voltage window from 1.0 V to 1.8 V, increasing the specific capacitance from 27 F g⁻¹ to 43 F g⁻¹, and ultimately achieving a fivefold enhancement in energy density (up to 18.8 Wh kg⁻¹).