Fabrication of Cu₂V₂O₇ nanoparticles and Cu₂V₂O₇/MXene composite as high-performance electrode for aqueous asymmetric supercapacitors: Role of electrolyte environment

Bimetallic vanadium oxides are found to be extremely suitable candidate for supercapacitors owing to their rich redox active sites, high theoretical capacitance, elevated energy density, impressive power output, and excellent cycling durability. So, in the present work, Cu₂V₂O₇ nanoparticles are synthesized using adoptable hydrothermal method and their supercapacitive properties are performed in three different electrolytes (LiOH, NaOH and KOH). The capacitance of Cu₂V₂O₇ in 2 M KOH is found to be 557 F g⁻¹, which is higher than 2 M LiOH (305 F g⁻¹) and 2 M NaOH (431 F g⁻¹). Further, specific capacitance of sole Cu₂V₂O₇ is improved by adding small amount of MXene (Ti₃C₂) and improved capacitance of 782 F g⁻¹ is obtained from Cu₂V₂O₇/MXene in 2 M KOH electrolyte. Furthermore, aqueous asymmetric supercapacitor (ASC) is assembled by Cu₂V₂O₇/MXene (positive electrode), activated carbon (AC) (negative electrode) and 2M KOH (electrolyte). Cu₂V₂O₇/MXene//AC delivers the maximum energy density of 38.04 Wh kg⁻¹ at 800 W kg⁻¹. Additionally, four light-emitting diodes (LEDs), thermometer/humidometer, toy motor fan and kitchen timer are functionalized separately by series-connected two Cu₂V₂O₇/MXene//AC devices.