Spray pyrolysis deposition of Tin Oxide for supercapacitor electrode application

Abstract

This study obtained a tin oxide (SnO₂) film via spray pyrolysis deposition on stainless steel substrate. Annealing was performed to improve the crystallinity and conductivity of the films. The as-prepared film was designated as AsP and those annealed at 400, 450 and 500^oC were designated as A400, A450 and A500, respectively. It was observed that A450 had the best electrochemical performance evaluated with cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). This was attributed to the densely-packed larger grains observed with a scanning electron microscope (SEM). The grain size was calculated from X-ray diffractometry (XRD) spectra and A450 was found to have bigger grains than AsP by 1.9 and 2.5 nm for reflections (110) and (200), respectively. A450 also had the smallest resistance values from fitting results in EIS. The maximum specific capacitance (C_sc) was 350.24 F/g at 10mV/s which is more than 300% than that of the as-prepared sample. This study produced a pure SnO₂ film with the highest measured C_sc value to date.