Fabrication of Ag-doped MnO₂ nanosheets@carbon cloth for energy storage device

In this article, we report an electrode of uniform and ultrathin nanosheets of silver-doped manganese oxide (Ag₂-MnO₂) synthesized on carbon cloth through a hydrothermal method with an outstanding specific capacitance for the high-performance aqueous asymmetrical supercapacitor. The Ag₂-MnO₂ electrode bears the highest specific capacitance of 350 F g⁻¹ at 1 A g⁻¹ and 280 F g⁻¹ at a current density of 40 A g⁻¹. Besides, an aqueous asymmetric supercapacitor (Ag₂-MnO₂//AC) assembled with Ag₂-MnO₂ as a positive electrode exhibits a wide potential window of 0–2.0 V and a remarkable energy density of 54 Wh kg⁻¹ at a power density of 2000 W kg⁻¹. Energy density of 26 Wh kg⁻¹ is retained even at a higher power density of 19500 W kg⁻¹. This device offers excellent cycling stability and capacitance retention of 80% after 10,000 GCD cycles.