Enhancing energy storage performance in quasi-solid-state supercapacitors fabricated by direct laser writing of graphene

Abstract

This study presents a method for enhancing the capacitive performance of laser-induced graphene electrodes used in supercapacitors by incorporating a conductive polymer. This addition improved the specific capacitance through the introduction of new capacitive and faradaic components. The performance of interdigitated graphene electrodes fabricated via direct laser writing was enhanced by approximately 200 % and 225 % in terms of specific capacitance and energy density, respectively, following modification with reduced graphene oxide, poly(methylene blue) nanoparticles, and a gel electrolyte with an extended electrochemical stability window. For the device exhibiting optimal performance, capacitance decomposition indicated that 21 % and 79 % of the capacitance were attributed to the diffusion and capacitive components, respectively, at a scan rate of 5 mV·s⁻¹. Moreover, this supercapacitor demonstrated remarkable cycling stability over 5000 cycles, retaining >91 % of its performance, whereas the Coulombic efficiency increased from 97.9 % to 100 %. These findings highlight the potential of this material for energy storage applications.