Combined Electrochemical and DFT Investigations of ZnCo<sub>2</sub>O<sub>4</sub>–WO<sub>3</sub>@Ti<sub>3</sub>C<sub>2</sub>T<i><sub>x</sub></i> MXene Nanofiber Nanocomposite as a Cathode for a High-Performance Flexible Asymmetric Supercapacitor
Rajeshvari Samatbhai Karmur, Sara Fernandes, Neha Neha, Nilesh Jaiswal, Krishna Aravind Padmalayam, Sarbani Ghosh, Anshuman Dalvi, Narendra Nath Ghosh
Abstract
High Resolution Image Download MS PowerPoint Slide Interfacial engineering offers an enticing approach to improving the charge-transfer kinetics in supercapacitor electrodes. Herein, a nanocomposite composed of WO 3 nanoplates decorated on the surface of ZnCo 2 O 4 (ZCO) nanopetals with the combination of Ti 3 C 2 T x MXene nanofibers (MXNFs) was successfully prepared. This nanocomposite (ZCO–WO 3 @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–WO 3 @MXNF was used as the positive electrode and MXene-rGO sp 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–WO 3 @MXNF//MXene-rGO sp 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.