Probing the Influence of Morphological Transformation on the Electrochemical Properties of Hydrated Tungsten Oxide (WO3-x.H2O) for High-Rate Aqueous Asymmetric Supercapacitor

Abstract

The present study aims to probe morphological tuning of hydrated tungsten oxide (WO3-x·H2O) nanostructures and their electrochemical performance investigation for energy storage in supercapacitors. The WO3-x·H2O nanostructures have prepared via a single-step wet chemical method. Further, the morphological transition of WO3-x·H2O nanostructures from nanosheet-assembled nanoflowers (W1) to nanoribbons (W2) as a result of regulating the reaction time has achieved without disturbing the orthorhombic crystal structure. The morphological transformation from W1 to W2 exhibited decrease in crystallinity and other physical properties significantly affecting electrochemical behavior. Electrochemical investigations emphasized that W1 has higher specific capacitance of 70 F g-1 than W2 of 37 F g-1 at 1 A g-1. Moreover, an Aqueous Asymmetric Supercapacitor (AASC) device fabricated using WO3-x·H2O as the negative electrode. The device exhibited a specific capacitance of 40 F g-1 at 0.5 A g-1 with an energy density of 12.5 W h kg-1 and a power density of 3784 W kg-1. Additionally, it demonstrated excellent cycling stability with 97 % capacitance retention over 5000 cycles. These findings highlight the potential of morphology-controlled WO3-x·H2O nanostructures for advanced energy storage applications.