Synthesis of vanadium oxides nanosheets as anode material for asymmetric supercapacitor

Vanadium oxides (V 2 O 5 ) have been intensely investigated for advanced supercapacitors due to its extensive multifunctional properties of typical layered structure and multiple stable oxide states of vanadium in its oxides. In this study, V 2 O 5 nanosheets are synthesized via V 2 O 5 xerogel solvothermal reaction in ethanol solvent at 200 °C for 12 h. The V 2 O 5 nanosheets facilitate the easy accessibility of ions and can provide more area available for electrochemical reactions. We have achieved the highest specific capacitance of 298 F/g and good rate discharge for V 2 O 5 electrodes. Notably, the capacitance still retains a high retention rate of 85% after 10,000 cycles at 200 mV/s. Furthermore, asymmetric supercapacitors is assembled based on V 2 O 5 nanosheets and active carbon electrode, and a specific capacitance of 13.2 F/g is obtained at 1 A/g, with a energy density of 4.7 Wh/kg at a power density of 0.798 kW/kg and remains 2.28 Wh/kg at 7.992 kW/kg. Based on these results, the asymmetric supercapacitor exhibits a good cycle life with 77.3% capacitance retention after 3000 cycles. It suggests that the V 2 O 5 nanosheets are promising electrode material for electrochemical supercapacitors.