Redox-active copper vanadate integrated with nitrogen-doped graphene oxide (CuV2O6/N-GO): a fiber-structured nanocomposite for symmetric supercapacitors

The advancement of supercapacitor technologies depends on the development of effective electrode materials with excellent conductivity, large surface area, and robust electrochemical stability. In this work, we report the synthesis of copper vanadium oxide (CuV₂O₆) integrated with nitrogen-doped graphene oxide (N-GO) using a straightforward hydrothermal method followed by thermal treatment. The addition of N-GO not only improves the composite’s electrical conductivity but also provides a conductive matrix that enables efficient charge transfer and rapid ion transport. The resulting CuV₂O₆/N-GO hybrid exhibits a well-connected, layered nanostructure characterized by a large specific surface area, promoting plenty of electroactive sites. Electrochemical characterization reveals an elevated specific capacity of 693 C g⁻¹ (1155 F g⁻¹) at 5 mV s⁻¹, along with excellent rate capability and cycling stability, retaining 81.39% of its capacity after 5000 cycles. A symmetric supercapacitor (SSC) device assembled using CuV₂O₆/N-GO as the positive and negative electrodes delivers an impressive energy density of 66.6 Wh kg⁻¹ and a power density of 2700 W kg⁻¹. The device sustained 75% capacitance retention over 3600 cycles.