Assessing Strong Consistency of Symmetrical Solid-state Supercapacitors Based on Three-dimensional Porous Carbon Material

Abstract Three-dimensional (3D) porous carbon material enhances the electrochemical performance of symmetrical solid-state supercapacitors which are prepared by using abundant biomass waste as electrodes and (PVA-Li2SO4) gel polymer electrolyte. A saving and simple carbonization method with KOH chemical activation is developed for synthesizing highly porous carbon from peanut shell with high specific surface area of 1348 m2 g–1, which can be reused the chemical activation solution. The electrodes making by such three-dimensional porous carbon in a 1 M Li2SO4 electrolyte demonstrates a maximum specific capacitance of 386 F g–1 at current density of 2 A g–1, energy density and power density of 53.61 Wh k g–1 and 1000 W kg–1, respectively. The symmetrical solid state supercapacitors with sandwich structure of (3D porous carbon P/PVA-Li2SO4/3D porous carbon P) exhibits a maximum specific capacitance of 116 F g-1 at current density of 0.5 A g–1. The energy density and power density are the value of 9 W h kg–1 and 380 W kg–1, respectively. Further, the supercapacitors also demonstrate good cycling stability 89 % retention after 7000 cycles.