Hierarchical micro tiles growth of monoclinic tungsten oxide nucleated on MWCNTs hexagonal skeleton: Wide potential solid-state supercapacitor with mechanical bendable design

Abstract

Material mutualism in the growth process empowering monoclinic tungsten oxide (W25O73) onto hexagonal multi-walled carbon nanotubes (MWCNTs) act as self-sacrificing template, enabled controlled micro tile surface architecture through simple chemical route. Formed monoclinic crystal structure of tungsten oxide (W25O73) is well confirmed through X-ray diffraction, and high-resolution transmission electron microscopy. Three electrode configured electrochemical analysis of the MWCNTs/W25O73 film exhibits high specific capacitance of 1301.46 F∙g^(-1) (areal 273.31 mF∙cm^(-2)) at scan rate of 1 mV∙s^(-1) with potential window of 0.94 V in 1 M LiClO4. Further, designed flexible symmetric solid-state supercapacitor device displays remarkable voltage window of 1.86 V aided through Li^+ ions embedded in the polyvinyl alcohol polymer matrix with specific capacitance of 259.24 F∙g^(-1) (areal 54.44 mF∙cm^(-2)) at 5 mV∙s^(-1) scan rate. Even after 10000 consecutive CV cycles, the device preserves 82.78 % of its initial capacitance, confirming reliable long term operational stability. In-depth scrutiny has been performed through power law calculations, diffusion and capacitive contributions, electrochemical impedance spectroscopy analysis. The device exhibited excellent mechanical flexibility of 99.62 % at bending angle of 170˚ along with the practical viability by powering small dc-fan and LED panel showcasing its potential candidature for future advanced application.