Energy storage performance of 2D MoS₂ and carbon nanotube heterojunctions in symmetric and asymmetric configuration

Excellent cyclic stability and fast charge/discharge capacity demonstrated by supercapacitors foster research interest into new electrode materials with 100% cycle life and high specific capacitance. We report an improvement in the electrochemical performance of MoS₂/multiwalled carbon nanotubes (MWCNT) nanohybrid and intensively explored its performance in symmetric and asymmetric supercapacitor (ASC) assembly. The symmetric assembly of MoS₂/MWCNT exhibits capacitance of around 274.63 F g^-1 at 2 A g^-1 with higher specific energy/power outputs (20.70 Wh kg^-1/1.49 kW kg^-1) as compared to the supercapacitor based on pristine MoS₂ (5.82 Wh kg^-1/1.07 kW kg^-1). On the other hand, a unique all-carbon-based ASC assembled with MoS₂/MWCNT and VSe₂/MWCNT composite with K₂SO₄ as electrolyte delivers the highest energy density of 32.18 Wh kg^-1 at a power density of 1.121 kW kg^-1 with exceptional cycling stability and excellent retention of about 98.43% even after 5000 cycles. These outstanding results demonstrate the excellent electrochemical properties of both symmetric and asymmetric systems with high energy density and performance, which further enable them to be a potential candidate for supercapacitor applications.