Graphene oxide from coconut shells for high-performance supercapacitor application

Globally, the demand for materials with high ultrafast charge rates yet slow discharge continues to rise which has resulted in extensive research into supercapacitors. Although the current supercapacitors can meet such demands, the high processing cost coupled with the use of toxic chemicals remains a major concern. In this study, porous graphene oxide (GO) with a unique morphology was synthesized by an improved Tour’s method for supercapacitor application using coconut shells as a precursor. The structure of the synthesized material consists of partially graphitized walls of porous GO. The surface morphology, the defects created in the GO, and the specific surface area of the as-synthesized materials were studied. When evaluated as an electrode material for supercapacitors, a specific capacitance of 173 F/g at 0.5 A/g in 0.5 M Na2SO4 and 139 F/g at 0.5 A/g in 2 M KOH was recorded. Moreover, a high capacitance retention of 99.3% was recorded after 1000 cycles, confirming the good cyclic stability of the synthesized electrode material. The good electrochemical performance can be attributed to the electrode material’s intrinsic structural and compositional superiorities. These findings indicate the potential of using coconut shells as a precursor for the synthesis of high-performance graphene-based supercapacitor electrodes with improved cost-effectiveness and reduced environmental impact.