All-solid-state flexible supercapacitor based on a binary transition metal dichalcogenide grown on 2D/2D heterostructure materials

The spellbound effect of two-dimensional (2D) materials over the industry of nanotechnology and opto-electronic devices is a trending topic during the past decade or so. Among the plethora of 2D materials, transition metal dichalcogenide (TMDs), MXenes and other graphene analogue materials have been frontiers in the research of energy storage application. To overcome the low energy density, long-standing restacking issues of these material-based supercapacitors, herein a facile in situ hydrothermal method has been reported for the synthesis of a ternary MoWS2@BCN@Ti3C2TX MXene as an electrode material for high performance and efficient all-solid-state supercapacitor device. The pristine, binary (MoWS2@BCN) and ternary (MoWS2@BCN@Ti3C2TX) electrodes are vividly characterized by various microscopy and spectroscopy techniques. The electrochemical studies revealed that the solid-state symmetric device exhibited an areal capacitance of 289 mF/cm2 at 0.6 mA/cm2 with the energy and power density of 19.73 μWh/cm2 and 538.09 μW/cm2 respectively. Further, device upheld a robust 91 % cyclic stability and 95 % coulombic efficiency over 5000 rhythmic charge-discharge cycles. The flexible all-solid-state device based on MoWS2@BCN@Ti3C2TX MXene ternary electrode can be a torch bearer for the real time application of efficient supercapacitors. Further to analyse the structural and electronic properties of binary and ternary electrodes, the first principle simulations are performed. We have presented the orbital interactions, charge transfer and quantum capacitance for binary and ternary hybrids. The estimated quantum capacitance has shown the improvement in an order which is in the same line as experimentally observed specific capacitance. The inter-layer interactions involve transfer of charge from the Mo 4d orbital of MoWS2 and C 2p orbital of BCN to the C 2p orbital of MXene which may be one of the basic driving forces behind the improvement charge transfer performance of ternary MoWS2@BCN@Ti3C2TX.