Biomass-derived graphene oxide-doped mesoporous carbons for supercapacitors: performance and post-cycling characterisation

Mesoporous carbons were synthesised from starch via the Starbon® methodology, a gelation-retrogradation process that avoids the use of templating agents and hazardous chemicals used for their removal. Graphene oxide (GO) nanoparticles were added to enhance conductivity and performance. Elemental analysis and Raman spectroscopy confirmed the carbonaceous, turbostratic nature of the produced materials, with nitrogen adsorption and scanning electron microscopy demonstrating the presence of multiple interconnected hierarchical pore networks spanning the micro-, meso-, and macroporous domains. Symmetrical supercapacitor cells were assembled with a 2M H 2 SO 4 solution electrolyte, demonstrating optimal performance at only 0.5 wt% GO, and achieving specific capacitances of ∼200 F/g and power densities of up to 6000 W/kg. Post-cycling characterisation of the electrodes following galvanostatic testing showed a more than two-fold increase in accessible pore volume and BET surface area, indicating the liberation of previously inaccessible porosity during operation. These findings highlight the potential of Starbon® -derived carbon nanocomposites as sustainable, high-performance supercapacitor electrodes and provide further insight into the evolution of carbonaceous electrodes during electrochemical cycling. • A green, novel approach was used to synthesise a range of sustainable, mesoporous carbons doped with graphite oxide nanoparticles. • Reduced graphene oxide greatly enhanced the conductivity and electrochemical performance of the carbon electrodes. • It was discovered that galvanostatic cycling determines the porosity of the final material, opening closed pores and creating new ones. • The mechanism of pore generation was investigated through a number of physico-chemical characterisation techniques (SEM, Raman, N 2 sorption porosimetry)