Oxygen-vacancy V2O5 ultrathin nanosheets adorned with PEDOT films as anodes for high-energy-density asymmetric supercapacitors†

Abstract

The development of asymmetric supercapacitors (ASCs) with high power and energy density is greatly restricted by the low capacitance of the anode materials. V₂O₅ is a promising anode material with high theoretical capacity, but its low conductivity and high dissolution are not conducive to applications in energy storage. Herein, oxygen-vacancy PEDOT/V₂O₅ ultrathin nanosheets with a thickness of about 4.4 nm are fabricated by the oxidative polymerization of EDOT monomers on V₂O₅ nanosheets in the absence of other oxidants. The results of XPS and EPR confirm that the polymerization of PEDOT increases the oxygen vacancy concentration of V₂O₅. The PEDOT/V₂O₅ nanosheets exhibit a specific capacitance of 406 F g⁻¹ at 2 mV s⁻¹ and excellent cyclic stability in the mixed organic electrolyte of dimethyl carbonate and ethylene carbonate. The energy density of ASCs composed of PEDOT/V₂O₅ as the anode and activated carbon as the cathode reaches 65 W h kg⁻¹ at a power density of 1490 W kg⁻¹. This means that PEDOT/V₂O₅ has enormous potential in high-energy storage.