Supercapacitor electrode properties of NiWO4 nanocrystals processed by thermal plasma and deposited on the FTO substrate

Abstract

In this communication, nickel tungstate (NiWO4) nanocrystals were prepared using the coprecipitation method at 90 °C for 6 h and processed by thermal plasma (TP) at 600 °C for 1 h. X-ray diffraction (XRD), Rietveld refinement data, micro-Raman, and Fourier transform infrared (FT-IR) spectroscopies were employed to analyze their structure and optical data. The morphology was observed through field emission scanning electron microscopy (FE-SEM) images. Moreover, their supercapacitor electrode properties were investigated in detail. XRD patterns, Rietveld refinement, micro-Raman/FTIR spectra, and FE-SEM images confirm pristine NiWO4 nanocrystals with a monoclinic structure, symmetric and antisymmetric stretch vibrations of ONiO and OWO bonds, which are related to IR- and Raman-active vibrational modes, spherical shape with average crystal sized ~29.2 nm. These NiWO4 nanocrystals present a high specific capacitance of 351.26 F g−1 at 40 mV s−1, in comparison with NiWO4 nanocrystals processed in heat treatment conventional (120 F g−1 at 40 mV s−1), which can be applied as a stable cathodic electrode. These results suggest that NiWO4 nanocrystals processed by TP and deposited on FTO substrate are good candidates for use as electrodes for energy storage devices in the next generation of batteries.