Cobalt-oxide/carbon composites for asymmetric solid-state supercapacitors

A facile methodology has been adopted for the synthesis of cobalt oxide (Co3O4) by we chemical technique followed by the calcination and prepared Co3O4/C composite for energy storage devices. Initially, SEM and XRD are carried out to analyze the surface characterizations of electrode material. The electrochemical properties of synthesized material has been investigated and the maximum specific capacitance of 567 F/g is achieved for Co3O4/C composite at 3 mV/s scan rate. Co3O4/C composite and activated carbon (AC) are sandwiching and separated with PVA-KOH-C gel electrolyte. The device has been examined at several scan rates and current densities demonstrating better performance with maximum energy density of 63 Wh/kg at 0.7 A/g. The capacitive retentivity is 82 % after 6000 charge/discharge cycles. The solid-state devices are showing a tremendous performance with high energy and power density and are safe to handle due to no seepage which can be utilized for the next generation.