Combined electrochemical and dft investigations of znco2o4–wo3@ti3c2tx mxene nanofiber nanocomposite as a cathode for a high-performance flexible asymmetric supercapacitor

Abstract

Interfacial engineering offers an enticing approach to improving the charge-transfer kinetics in supercapacitor electrodes. Herein, a nanocomposite composed of WO3 nanoplates decorated on the surface of ZnCo2O4 (ZCO) nanopetals with the combination of Ti3C2Tx MXene nanofibers (MXNFs) was successfully prepared. This nanocomposite (ZCO–WO3@MXNF) exhibited superior electrochemical performance over its components. Density functional theory (DFT) calculations revealed the improvement of structural stability, charge-transfer efficiency, and electron mobility in the nanocomposite because of the presence of hybridized states throughout the composite and hence the enhancement of its electrochemical properties. The ZCO–WO3@MXNF was used as the positive electrode and MXene-rGOsp as the negative electrode to design the asymmetric supercapacitor (ASC) device. Notably, the fabricated solid-state ASC device offered the energy density of 16 Wh kg–1 at a power density of 204 W kg–1, with the remarkable stability of 93% specific capacitance retention even after ∼5000 charging–discharging cycles. Further, the study of the ZCO–WO3@MXNF//MXene-rGOsp ASC device in a pouch cell assembly was conducted. The pouch cell showed excellent performance, with an energy density of 28 Wh kg–1 and a power density of 578 W kg–1. The fabricated device showed its practical feasibility by lighting up the light-emitting diode (LED) lights. These results suggested its excellent electrochemical activity and its candidacy as a promising electrode material for energy storage devices.