Reconciled Nanoarchitecture with Overlapped 2 D Anatomy for High-Energy Hybrid Supercapacitors

A unique and novel, flower bouquet-like, vanadium disulfide (VS₂) nanosheet structure with very small prominent VS₂ nanoparticles (10–25 nm) anchored on the surface of graphene nanosheets (VS₂/G) was synthesized by a facile solvothermal method. The material showed superior electrochemical performance upon testing as a supercapacitor and achieved specific capacitance values of 211 and 135 F g⁻¹ at current densities of 1 and 20 A g⁻¹, respectively, with 97 % capacitance retention after 8000 cycles at 5 A g⁻¹ with high coulombic efficiency. The material was used to fabricate a full-cell hybrid supercapacitor (HSC), which showed a specific capacitance of 132 F g⁻¹ at a current density of 1 A g⁻¹ with remarkable cyclability up to 8000 cycles at 5 A g⁻¹ and a loss of less than 1×10⁻⁴ F cycle⁻¹. The HSC demonstrated an excellent energy density of 46.93 Wh kg⁻¹ at a power density of 0.91 kW kg⁻¹ and retained a high energy density of 23.11 Wh kg⁻¹ even upon increasing the power density tenfold (9.40 kW kg⁻¹). This unique material synthesized by a simple method is a very promising candidate for next-generation energy-storage technologies that can fill the gap between batteries and supercapacitor devices.