Hierarchical graphene-quinone-amine polymer nanocomposites with redox activity for high-performance flexible supercapacitors

Abstract

Quinone-amine polymers possess unique unsaturated hexagonal rings along with adjacent or separated carbonyl groups, which enable efficient charge storage and excellent electrochemical performance through reversible redox reactions. These polymers are extensively utilized in supercapacitor electrodes. In this study, we synthesized a graphene-based quinone-amine polymer composite, denoted as PBDQ@rGO. PBDQ effectively prevents the restacking of graphene layers while introducing pseudocapacitive behavior, whereas reduced graphene oxide (rGO) enhances electrical conductivity and rate capability. The synergistic interaction between PBDQ and rGO facilitates improved ion transport and overall electrochemical performance. The PBDQ@rGO-1 composite exhibits a specific capacitance of 674.5 F g⁻¹ at a current density of 0.5 A g⁻¹, retains 80.86 % of its capacitance at a high current density of 50 A g⁻¹, and maintains 73.22 % of its initial capacity after 25,000 cycles. Furthermore, PBDQ@rGO-1//AC flexible asymmetric solid-state supercapacitors (FASCs) exhibit a specific capacitance of 98.7 F g⁻¹ at 0.5 A g⁻¹, retaining 83.0 % of its capacitance after 5,000 cycles at 10 A g⁻¹ , and achieving an energy density of 34.18 Wh kg⁻¹ at a power density of 394.8 W kg⁻¹. The FASC demonstrates outstanding mechanical stability under bending and twisting deformations, maintaining its electrochemical performance after 5000 cycles. In-situ and ex-situ characterization techniques were employed to elucidate the underlying energy storage mechanisms, providing a foundation for the rational design of quinone-based electrode materials.