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.