Investigating and optimizing the variation of selenium infused MoS2 as electrode material for supercapacitor applications

Molybdenum disulfide (MoS₂) has been immensely explored for its potential usage in energy storage applications owing to its high theoretical specific capacitance and layered structure. Here, we have investigated the effect of selenium addition in MoS₂ forming MoS_2(1-x)Se_2x alloys and studied their electrochemical performance. Selenization was performed through a simple hydrothermal method. The electrochemical performance of MoS₁Se₁ was evaluated in a two-electrode configuration. The selenization is found to improve the electrochemical performance of MoS₂ and the MoS₁Se₁ alloy with the optimal S (sulfur) to Se (selenium) ratio of 1:1 exhibits an excellent areal capacitance of 2629.45 mF/cm² at 1 mA/cm², with an appreciable specific capacitance of 266.51 F/g at a current density of 0.5 A/g and excellent cycle stability of 81.64 % after 6000 cycles. Along with the experimental findings, Density functional theory calculations were also performed, revealing that the electronic properties of MoSSe systems can be tuned by varying the ratio of S and Se.