Nanostructured stannic oxide: Synthesis and characterisation for potential energy storage applications

SnO₂ nanoparticles were synthesized using the hydrothermal technique. Well crystalline particles with different morphologies and crystallite size in the range of 2 nm–10 nm were obtained by using Urea and Soduim Borohydride as reducing agents, and deploying Dioctyl Sulfosuccinate Sodium Salt (AOT) and Cetyl Trimethyl ammonium bromide (CTAB) as the surfactants. Samples have been characterised by X-ray diffraction, Scanning Electron microscopy, Energy Dispersive X-ray spectroscopy, specific surface area, porosity, and Fourier Transform Infrared spectroscopy. Preliminary studies on the potential electrochemical properties of the as-produced nanoparticles were investigated using cyclic voltammetry, electrochemical impedance spectroscopy and potentiostatic charge-discharge in aqueous KOH electrolyte. The surfactant and reducing agents used in the synthesis procedure of SnO₂ nanoparticles influenced the particle size and the morphology, which in turn influenced the capacitance of the SnO₂ nanoparticles. The SnO₂ electrode material showed pseudocapacitor properties with a maximum capacitance value of 1.6 Fg⁻¹ at a scan rate of 5 mVs⁻¹, an efficiency of 52% at a current of 1 mA and a maximum capacitance retention of about 40% after 10 cycles at a current of 1 mA. From the Nyquist plot, The ESR for the samples increase accordingly as SCA (31.5 Ω) < SAA (31.85 Ω) < SE (36.3 Ω) < SAT (36.92 Ω) < SCT (40.41 Ω) < SA < SC (53.97 Ω). These values are a confirmation of the low capacitance, efficiencies and capacitance retention recorded. The results obtained demonstrate the potential electrochemical storage applications of SnO₂ nanoparticles without the addition of conductive materials.