Exploring Self-Doped Conjugated Polyelectrolytes for All-Polymer Solid-State Supercapacitors

High Resolution Image Download MS PowerPoint Slide In this work, we explore the application of self-doped conjugated polyelectrolytes (CPEs) in all-polymer solid-state supercapacitors, aiming to develop safe, flexible, and environmentally friendly energy storage systems. Using poly[2,6-(4,4-bis-potassium butanylsulfonate-4 H -cyclopenta-[2,1- b; 3,4- b ′]-dithiophene)- alt -4,7-(2,1,3-benzothiadiazole)] (commonly referred to as CPE-K) as the electrode material, we fabricated both symmetric and asymmetric supercapacitor devices. A biodegradable poly(vinyl alcohol)/sulfuric acid (PVA/H 2 SO 4 ) gel served as the electrolyte in both configurations, while poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid) (PEDOT:PSS) was employed as the anode in the asymmetric setup. Electrochemical characterization showed that symmetric CPE-K devices achieved a specific capacitance of 28.13 F g –1, an energy density of 1.41 Wh kg –1, and operated within a voltage window of 0.6 V. In contrast, the asymmetric devices extended the voltage window to 1.6 V, delivering a maximum energy density of 6.01 Wh kg –1 at a current density of 1 A g –1, surpassing the performance of symmetric PEDOT:PSS-based devices. Both configurations demonstrated excellent cycling stability and Coulombic efficiency. Mechanical and thermal abuse tests confirmed the robustness of the solid-state architecture with capacitance enhancements under compressive pressures up to 8 MPa and stable operation at temperatures up to 100 °C. These findings underscore the potential of conjugated polyelectrolyte-based supercapacitors for next-generation energy storage applications that demand mechanical resilience and thermal safety.