Direct Powder Adhesion Method of Quinone-Based Aqueous Supercapacitor for Roll-to-Roll Process

Abstract

Quinone-based supercapacitors have been a growing research target as the next generation energy storage due to their high energy density and their environmental sustainability. However, the commercialization of these organic supercapacitors remains challenging due to complex fabrication processes and insufficient electrochemical performance. In this study, we introduce a novel fabrication method, direct powder adhesion (DPA), which simplifies electrode production while enhancing rate performance. Compared to conventional multi-step pressing methods, the DPA technique produces electrodes with lower density (0.48 g cm⁻³ vs. 0.52 g cm⁻³) and significantly improves conductivity (0.74 Ω cm vs. 1.98 Ω cm). Electrochemical testing of quinone-impregnated electrodes demonstrates a high specific capacity of 217 mAh g⁻¹ at 0.5 C. The DPA method demonstrated 3.5 -fold increase in the specific capacity at 5 C compared to the conventional method, showing high reversibility at higher C rates. Even when the electrode was scaled up by more than >8 times to a more practical size, the same specific capacity of 217 mAh g⁻¹ at 0.5 C was achieved, demonstrating excellent scalability. Despite some challenges with high overpotential at higher rates, this study takes a significant step toward the mass production of high-performance organic supercapacitors.