High performance in situ annealed partially pressurized pulsed laser deposited WO3 & V2O5 thin film electrodes for use as flexible all solid state supercapbatteries

Abstract

Flexible all solid-state hybrid supercapacitors (HSCs) are considered to be significant energy storage devices and are used as major power sources in various real-time applications. Herein, we fabricated highly crystalline tungsten trioxide (WO₃)‖vanadium pentoxide (V₂O₅) thin film supercapbatteries in which WO₃ and V₂O₅ showed pseudo-capacitive and battery type behavior, respectively. For the first time, WO₃ ‖V₂O₅ thin film based combination has been investigated in this work. The thin film structured electrodes used in this study were prepared in partially pressured, in situ annealing conditions using the pulsed laser deposition (PLD) technique. The as prepared 1.5 V solid state hybrid device delivered a maximum volumetric capacitance of 40.28 F cm⁻³ at 0.1 mA cm⁻². A maximum specific energy density of approximately 12.58 mW h cm⁻³ at a specific power density of 0.316 W cm⁻³ was also achieved. Furthermore, the device showed an excellent round trip efficiency of 99.4%, even after 50 000 cycles, with a capacitance retention of 95.2%. The performance characteristics of the hybrid device were also compared with the V₂O₅‖V₂O₅ and WO₃‖WO₃ symmetric devices which showed a superior performance compared to the symmetric devices. In addition, the functions of the device with regards to various engineering aspects, such as the flexibility, twisting nature, and folded conditions, were demonstrated successfully. Furthermore, light-emitting diodes (LEDs) powered using the HSCs confirmed the potential applications of such devices in wearable and portable devices.