Cobalt-Doped Vanadium Sulfide Nanorods Anchored on Graphene for High-Performance Supercapacitors

Supercapacitors (SCs) have gained widespread recognition because of their advantageous power density as energy storage devices; it is still a great challenge to design a high-efficiency electrode material with outstanding energy density. In this work, nanorod-like cobalt-doped vanadium sulfide on a graphene nanosheet (Co-VS₄/G) is successfully developed with a distinct nanostructure by employing a scalable solvothermal process. The morphology and structure of Co-VS₄/G were explored to prove the Co doping well into the crystalline of VS₄ architecture. This creates more defects and brings about rich redox reactions, resulting in enhanced electrochemical performance. Noticeably, the fabricated Co-VS₄/G composite exhibits a specific capacitance of 1230 F g^–1 at 1 A g^–1 with a rate capability of 796 F g^–1 at a current density value of 30 A g^–1 and cycling performance with 88.9% retention of its initial capacitance after 10,000 cycles. Furthermore, the as-fabricated Co-VS₄/G//rGO asymmetric supercapacitor (ASC) device presents an energy density value of 75.8 W h kg^–1 at a power density of 0.791 kW kg^–1 and cycling stability with 91.1% of its capacitance following 10,000 cycles. The performance of the rodlike Co-VS₄/G composite shows a predominant advantage toward the development of effective energy storage systems.