WS₂-embedded MXene/GO hybrid nanosheets as electrodes for asymmetric supercapacitors and hydrogen evolution reactions

MXene-related materials are auspicious electrodes for energy storage/conversion application due to their various features, including large surface area, high metallic conductivity, and fast redox activity; however, their surface aggregation and oxidation have significantly restricted their application in various industries. This study demonstrated the fabrication of porous WS₂ nanosheets-interconnected MXene/GO (WS₂@MXene/GO) nanocomposites using a simple hydrothermal reaction for electrochemical supercapacitors and water splitting reactions. The assembled WS₂@MXene/GO nanocomposites electrode produced a superior specific capacitance of ∼ 1111F g⁻¹ at 2 A/g applied current. Further, the asymmetric device constructed using the nanocomposite delivered the high specific energy of ∼ 114 Wh kg⁻¹ and asymmetric capacitance of 320F g⁻¹ along with an exceptional cycling stability. The WS₂@MXene/GO nanocomposites electrocatalyst exhibited low overpotentials of 42 and 45 mV and small Tafel slopes values of 43 and 58 mV.dec⁻¹ for hydrogen evolution reaction in acidic and alkaline medium, respectively. In addition, density functional theory (DFT) approximations validated the observed experimental results using density of states, Gibbs free energy for H-adsorption, and quantum capacitance calculations.