High‐Performance Supercapacitors Fabricated from Sugarcane Waste‐derived Activated Carbon Electrodes and Carbon Dot‐added Molasses as Electrolytes

Abstract

In this work, bio‐renewable, high‐performance supercapacitors were prepared from sugarcane wastes. Activated carbon and carbon dots (CDs) was prepared from sugarcane bagasse and leaves, whereas electrolyte, for the first time in any kind of electrochemical device, was prepared from molasses. The supercapacitors were then fabricated from activated carbon electrodes and molasses electrolyte. The supercapacitors using bagasse‐ and leaf‐derived activated carbon and molasses aqueous solution yielded a specific capacitance of 101 and 80 F g−1, respectively, at a scan rate of 30 mV s−1. When the molasses electrolyte was prepared in H2SO4 solution, the specific capacitance increased to 308 and 268 F g−1, respectively. Interestingly, when the CDs were added to molasses/H2SO4 electrolyte, the specific capacitance was further boosted to 456 and 356 F g−1, which are equivalent to 148 % and 133 % increases. In addition to enhancing the specific capacitance, the use of CDs also improved the cycling stability of the supercapacitors. A combination of enhanced surface capacitance and reduced interfacial resistance offered by the CDs led to a significantly enhanced performance. This work thus demonstrates a value‐adding strategy for sugarcane wastes and the fabrication of novel, high‐performance supercapacitors.