Robust, Flexible, and Binder Free Highly Crystalline V2O5 Thin Film Electrodes and Their Superior Supercapacitor Performances

摘要

Modern wearable technologies require highly efficient energy storage devices for improving their performance attributing a controlled shape and flexibility. Here, the present study is focused on the fabrication of a highly improved V_(2)O_(5) thin film based?supercapacitor. Symmetric device of V_(2)O_(5)||PVA-KOH||V_(2)O_(5) was fabricated using thin flexible electrodes prepared by a thermal evaporation technique. The symmetric supercapacitor devices were fabricated using both annealed and as-prepared films separately, and their performance characteristics were compared. The V_(2)O_(5) symmetric device having pseudocapacitive behavior delivered a maximum specific areal capacitance of 9.7 mF cm~(–2) at a scan rate of 10 mV s~(–1). The symmetric microcapacitor also showed promising performance even after being bent at 60 and 120°. This indicates the reliability of the fabricated devices for flexible electronic applications. Moreover, the symmetric capacitor showed excellent capacitance retention (95%)?even after 30?000 cycles with the coulombic efficiency of?99%. Furthermore, practical feasibility of the as fabricated devices was demonstrated by lighting blue light-emitting diodes by connecting them in series. On the other hand, characteristics of the V_(2)O_(5) thin films were also studied using X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, and atomic force microscopy analysis.