Investigation of graphene transition metal oxide nanocomposites for high performance supercapacitors

Abstract

The rising global demand of reliable and portable power sources leads to the emergence of energy storage devices. Today, electrical energy storage has been solely found in the area of batteries and capacitors. Supercapacitors bridge the functional gap newlinebetween traditional electrolytic capacitors and rechargeable batteries. They are well newlinesuited for applications that expect frequent charge discharge cycles, extreme operating newlinetemperatures and rapid discharge of high amount of energy. Presently, supercapacitors newlineare being fabricated using activated carbon as an electrode material due to its large newlinespecific surface area, low price, etc. At higher current densities it has low capacitance stability which limits its use at industrial level. For the advancement in energy storage systems, we require an ideal electrode material with high capacitance and wide potential window. Among the two-dimensional materials, graphene and its derivatives are considered as the most desired materials for the futuristic applications. The coupling of graphene with transition metal oxides would effectively improve the specific capacitance, cycling stability, energy and power density of the supercapacitor device. In the current doctoral research, we emphasized on graphene-transition metal oxide nanocomposite as an ideal electrode material with high specific capacitance, cyclic stability and energy density to fabricate the symmetric supercapacitors for an application level use. newlineThe present work investigates the electrochemical properties of prototype symmetric supercapacitor devices using transition metal oxide electrodes and electrodes fabricated using nanocomposites of reduced graphene oxide (rGO) and transition metal oxides (TMOs). The transition metal oxides studied are cobalt oxide (Co3O4), newlinemolybdenum trioxide (MoO3), and manganese oxide (Mn3O4), which were synthesized newlineusing the hydrothermal method.