Synthesis, characterization and supercapacitive application of nanocauliflower-like cobalt tungstate thin films by successive ionic layer adsorption and reaction (SILAR) method

•For the first time, CoWO4 thin film was synthesized using successive ionic layer adsorption and reaction (SILAR) method.•CoWO4 thin film offered specific surface area of 60 m2 g−1.•The highest electrochemical Cs of 1436.5 F g−1 at the scan rate of 2 A g−1 is obtained for CoWO4 thin film.•A FSS-SSC device of configuration CoWO4/PVA-KOH/CoWO4 showed specific energy of 14.07 Wh kg−1 at specific power 1225.25 W kg−1.•The FSS-SSC device showed Cs of 101.32 F g−1 at the scan rate of 2 A g−1 and exhibited excellent cyclic stability of 83.84%. For the first time, cobalt tungstate (CoWO4) thin films were synthesized by successive ionic layer adsorption and reaction (SILAR) method. The monoclinic crystal structure of CoWO4 film was confirmed from X-ray diffraction (XRD) technique. The elemental, surface morphological, structural, and electrical analyses were executed using Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray analysis (EDAX), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), two point probe method, and contact angle measurement techniques. The surface morphology of CoWO4 thin film consisted of islands of agglomerated cauliflower-like spherical nanoparticles with hydrophilic nature. The specific surface area of 60 m2 g−1 with an average pore size of 1.10 nm. The CoWO4 thin film electrode exhibited specific capacitance of 1436.5 F g−1 at a scan rate of 2 mV s−1 in 1 M KOH as well as capacitance retention of 94% over 3000 galvanostatic charge discharge (GCD) cycles. Furthermore, flexible solid-state symmetric supercapacitor (FSS-SSC) device assembled using CoWO4 thin films, showed specific capacitance of 101.32 F g−1, specific energy of 14.07 Wh kg−1 and specific power of 1225.25 W kg−1. This work highlights simplistic preparation of CoWO4 thin films for energy storage application. [Display omitted]