Hydrothermal Synthesis of MSe2 (M = Mn, Ni) on the MoSe2@MWCNT Composite: Advancing Supercapacitor Electrode Efficiency

Binary composites of transition metal dichalcogenides and carbon nanotubes have poor electrochemical stability, and this is mostly because developed composites usually have random structures that limit ion diffusion and provide less volume for ions to expand during reversible storage. We report the synthesis of MnSe₂ and NiSe₂ on MoSe₂@MWCNT binary composite using a hydrothermal technique for application as supercapacitor electrodes in energy storage devices. The incorporation of nanostructures resulted in a ternary composite with strong synergy, which has a higher capacity compared to the MoSe₂@MWCNT binary composite. The specific capacities of 1269 and 815 F g^–1 were obtained, respectively, for the ternary nanocomposite with MnSe₂ and NiSe₂ in the potential of −0.2 to 0.8 V. With a remarkable cycle life extending up to 3000 cycles, the MnSe₂/MoSe₂@MWCNT and NiSe₂/MoSe₂@MWCNT electrodes exhibit impressive capacity retention of 99% and 97%, respectively. Notably, the MnSe₂/MoSe₂@MWCNT electrode demonstrates superior ionic interaction, facilitated by the presentation of multiple electrochemically active sites. Consequently, this results in reduced resistance and accelerated ion transmission. Nevertheless, both composites emerge as highly promising candidates for efficient energy storage applications.