Solid-state asymmetric supercapacitor based on manganese dioxide/reduced-graphene oxide and polypyrrole/reduced-graphene oxide in a gel electrolyte

• Fabrication of MRI/PRI ASC with simple and efficient electrochemical deposition technique.
• The MRI/PRI ASC exhibited a significantly improve capacitive performance in comparison with that of symmetric supercapacitor.
• The effect of mass ratio of MRI/PRI electrode on the electrochemical properties of the ASC was carefully investigated.
• Development of solid state and micro-size electrodes for green and low cost energy storage.

Manganese dioxide/reduced graphene oxide/indium tin oxide (MRI) and polypyrrole/reduced graphene oxide/indium tin oxide (PRI) electrodes were prepared via the chronopotentiometric-deposition of either manganese oxide or polypyrrole, respectively, onto a RGO/ITO film at a constant current density. Solid-state asymmetric supercapacitors (ASC) were assembled using MRI as the positive electrode and PRI as the negative electrode in a PVA/LiCl gel electrolyte. These devices displayed a power density of 7.4 kW/kg (for an energy density of 13 Wh/kg), an energy density of 16 Wh/kg (for a power density of 0.3 kW/kg), and a capacitance retention of 75% over 2000 cycles. The MRI//PRI ASC exhibited a much improved capacitive performance compared to the symmetric PRI//PRI (3 Wh/kg at 0.47 kW/kg) and MRI//MRI (9 Wh/kg at 0.12 kW/kg) supercapacitors. The superior capacitive performance of the MRI//PRI ASC was ascribed the improved conductivities and mechanical stabilities of MRI and PRI electrodes, obtained by preparing the polypyrrole and manganese oxide films on a graphene-coated electrode.

Solid-state asymmetric supercapacitors (ASC) are fabricated from an anode of manganese dioxide/reduced graphene oxide/indium tin oxide (MRI) and a cathode of polypyrrole/reduced graphene oxide/indium tin oxide (PRI). In addition to the improvement in electrochemical performance of the devices compares to the symmetric supercapacitor, the easy fabrication method, environmentally benign and low-cost for packaging, make the ASC potential candidates for application in energy storage.Figure optionsDownload as PowerPoint slide