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

Abstract

A Mn 3 O 4 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 Mn 3 O 4 nanocrystals and reduced graphene oxide (rGO) sheet/scrolls. As electrode material for supercapacitors, MRNC reaches a specific capacitance of 611 F g À1 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 Wh kg À1 and 833 W kg À1 , 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.[a] Dr.

Binder Free and Flexible Asymmetric Supercapacitor Exploiting Mn3O4 and MoS2 Nanoflakes on Carbon Fibers

“…The devices with hydrogel were cycled at 200 mV s −1 up to 3000 scans, showing a capacitance retention of 80%, which could be increased indeed by improving the packaging and sealing. The performances of the two devices are compared in Figure 5 d, with the literature on supercapacitors in which MoS 2 and MnO 2 were employed on steady Ni-foam current collectors and cellulose separator soaked of hydrogel [ 62 ], bendable supercapacitors in which one of the electrodes includes a flexible carbon-based current collector decorated with MoS 2 [ 63 , 64 , 65 , 66 , 67 , 68 , 69 ] with Mn 3 O 4 [ 70 , 71 , 72 , 73 , 74 , 75 ] , or specifically with carbon fibers coated with MnO 2 [ 76 , 77 ]. In particular, at powers from 9000 to 450 W/kg, the device in this study based on liquid electrolyte delivers from 14 to 29 Wh/kg, while that with hydrogel delivers 1 to 31 Wh/kg.…”

Polypyrrole nanowires as a cathode microporous layer for direct methanol fuel cell to enhance oxygen transport

“…The bands at 1302 and 1174 cm −1 are attributed to vibrations of CN and CN + , respectively 35,36 . The two bands at 1040 and 910 cm −1 are in‐plane bending and vibration of CH, respectively 37 . The peak at 780 cm −1 evidences that the pyrrole was polymerized 38 .…”

“…35,36 The two bands at 1040 and 910 cm −1 are inplane bending and vibration of C H, respectively. 37 The peak at 780 cm −1 evidences that the pyrrole was polymerized. 38 The XPS spectrum shows that carbon, nitrogen, and oxygen elements are present in the sample ( Figure S1 in Data S1).…”

α‐MnO2‐Sensitized SrCO3−Sr(OH)2 Supported on Two‐Dimensional Carbon Composites as Stable Electrode Material for Asymmetric Supercapacitor and Oxygen Evolution Catalysis

“…Thus, the presence of mesoporous structure and large pore volume of MSSG-1 nanocomposites would facilitate the bulk diffusion of electrolyte ions during the rapid charging/discharging process. [58,59]…”