Combining in-situ sedimentation and carbon-assisted synthesis of Co3O4/g-C3N4 nanocomposites for improved supercapacitor performance

Co3O4 has been extensively studied as a potential electrode material for supercapacitors. However, it has some limitations such as low conductivity and ion diffusion that have hindered its widespread application. To overcome the low electron transport efficiency of Co3O4 electrodes, a combination of in-situ precipitation and carbon-assisted methods were performed to synthesize a composite consisting of Co3O4 uniformly dispersed on the surface of graphitic carbon nitride (Co3O4/g-C3N4). In this work, electrochemical measurements in a 6 M KOH electrolyte reveal that the Co3O4/g-C3N4 composite electrode exhibits a higher specific capacitance (1071 F g(-1) at a current density of 1 A g(-1)) than the pure Co3O4 electrode (217 F g(-1) at 1 A g(-1)). After 4000 cycles, the capacitance remains 80% of its original value. The Co3O4/g-C3N4 electrode also showed excellent electrical conductivity and low resistance, as determined using electrochemical impedance spectroscopy. Moreover the Co3O4/g-C3N4//AC asymmetric device with this electrode delivered energy density is 20.4 Wh kg(-1) at the power density is 0.8 kW kg(-1). The results illustrate that Co3O4/g-C3N4 composites show great promise for application in supercapacitors.