Improving the rate capability of microporous activated carbon-based supercapacitor electrodes using non-porous graphene oxide

In this work, high-rate-capability supercapacitor electrodes based on a green, sustainable, graphene oxide-assisted microporous activated carbon (AC) were developed by a facile method. Highly microporous ACs were produced from tea factory waste using different amounts of potassium carbonate (K2CO3). Non-porous GO sheets were prepared by anodic electrochemical exfoliation in a 0.1 M (NH4)(2)SO4 aqueous solution. The materials were characterized by N-2 adsorption-desorption, particle size, XPS, Raman, and SEM techniques. The electrochemical performance of ACs was examined by using a 6 M KOH electrolyte with CV, GCD, and EIS methods. It was determined that the activated carbon sample (AC-IR1.5), prepared using a mass ratio of (1.0:1.5) of tea factory waste: K2CO3, exhibited the best electrode performance. These highly reversible best-performing AC-based electrodes prepared from AC-IR1.5 with the highest micropore volume fraction were physically mixed with GO in mass ratios, (AC-IR1.5: GO) of 90:10, 75:25, 60:40, and examined as the supercapacitor electrodes along with AC-based electrodes. The electrochemical characterization results showed that a significant enhancement in the rate capability was achieved by AC-IR1.5: GO electrodes compared to AC-based ones. The capacitance retention of AC-IR1.5: GO (75:25) was found to be at least twice as higher (84%) than that of AC-based electrodes (39%) at a high current density of 10 A g(- 1).

Automated summary

High-rate-capability supercapacitor electrodes were developed using a green and sustainable graphene oxide-assisted microporous activated carbon (AC). The ACs were produced from tea factory waste using different amounts of potassium carbonate (K2CO3), while the non-porous GO sheets were prepared by electrochemical exfoliation. The best electrode performance was achieved by the AC sample prepared with a mass ratio of (1.0:1.5) of tea factory waste: K2CO3. Mixing this AC with GO improved the rate capability significantly, with AC-IR1.5: GO (75:25) exhibiting a capacitance retention twice as high as AC-based electrodes at a high current density of 10 A g(- 1).