Cobalt oxide decorated 2D MXene: A hybrid nanocomposite electrode for high-performance supercapacitor application

The 2D layered material, MXene has incited a lot of interest in energy storage research due to its high metallic conductivity, high hydrophilicity, high energy storage capability, biocompatibility, and excellent electrochemical activity due to rich surface chemistry. However, the restacking of MXene layers lowers the number of active sites in MXene, which in turn limits the use of MXene in supercapacitors. Furthermore, the narrow working potential window of MXene limits the energy density of the electrodes. To address these issues and improve the electrochemical performance of MXene, several hierarchical MXene/transition metal oxide composites have been synthesized and characterized. This work explores MXene and its composites with cobalt oxide nanoparticles for supercapacitor applications. The Co@MXene composite was synthesized by using a one-pot hydrothermal method. As prepared, the nanocomposite exhibited a specific capacitance of 732.5 F g−1 at 1 A g-1 current density and excellent cycling stability of 83% over 5000 cycles. The as-fabricated ASC device (Co@MXene-2//AC) demonstrates the maximum energy density of 26.6 Wh Kg−1 at 700 W Kg−1 power density. The above results illustrate that MXene/transition metal oxide nanocomposite can be an alternative to enhance electrochemical performance for energy storage applications.