Solid State Supercapacitor Based on Manganese Oxide@Reduced Graphene Oxide and Polypyrrole Electrodes

A Mn3O4 nanocrystals@reduced graphene oxide nanocomposite (MRNC) is prepared using a hydrothermal method. Structural analysis of the synthesized MRNC shows the formation of tetragonal hausmannite phase of Mn3O4 nanocrystals and reduced graphene oxide (rGO) sheet/scrolls. As electrode material for supercapacitors, MRNC reaches a specific capacitance of 611 Fg(-1) with excellent stability showing a cycling stability of 95% after 3000 cycles. In addition, polypyrrole (PPy) films with various thicknesses are deposited on flexible carbon fiber via electrodeposition method. A solid state asymmetric supercapacitor (ASC) based on MRNC as positive and PPy as negative electrode was assembled. The assembled ASC delivers a maximum energy density and power density of 32 Whkg(-1) and 833 Wkg(-1), respectively, with excellent cycling stability (90% capacitance retention after 6000 cycles). The result reveals that the MRNC is a promising candidate as superior electrode material for supercapacitors.