All vanadium-based Li-ion hybrid supercapacitor with enhanced electrochemical performance via prelithiation

We report on the fabrication of an all-vanadium based Li-ion hybrid supercapacitor whose performance is highly enhanced compared to either batteries or supercapacitors via prelithiation process. Orthorhombic vanadium oxide nanoparticles and amorphous vanadium phosphate nanosheets implemented with carbon nanotubes are applied to battery-type and capacitive electrode, respectively. By utilizing vanadium-based electrodes with different charge-storage mechanisms in one device, advantages of both supercapacitors and batteries can be achieved. After a simple short-circuit prelithiation, the fabricated hybrid supercapacitor exhibits a high electrochemical performance with a capacitance of 111.6 F g⁻¹ at 10 mA g⁻¹, operation voltage window of 3.2 V, energy density of 160.2 Wh kg⁻¹ and power density of 4.484 kW kg⁻¹. Furthermore, it retains 98.3% of its initial capacitance after 2000 charge-discharge cycles. Due to its high operation voltage, a single, fully-charged hybrid supercapacitor successfully lights up variously colored LEDs for longer than one hr. With energy stored in the hybrid supercapacitor, a fragmentized graphene foam based strain sensor is powered to monitor various body-movements. This study demonstrates the high potential of the vanadium-based Li-ion hybrid supercapacitor as a powerful energy storage device obtained via deliberate selection of materials and prelithiation process.