Temperature-dependent structural and optical properties of Sb-doped SnO2 nanoparticles and their electrochemical analysis for supercapacitor application

Abstract

Transparent conducting oxides (TCOs) play an important role in advanced energy harvesting and storage systems, as well as cutting-edge display technology. In this study, we successfully synthesized antimony-doped tin oxide nanoparticles (Sb–SnO₂ (ATO)) employing the sol–gel technique, a well-established and facile method. The resulting ATO powder was meticulously analysed utilizing scanning electron microscopy and X-ray diffraction to reveal the intricate aspects of its crystallite phase and morphological structure. Our findings elucidated that elevating the calcination temperature led to enhanced crystallinity and increased crystallite size, while preserving the tetragonal structure. The electrochemical investigations were performed employing the ATO nanoparticles prepared at temperatures of 500 °C and 1100 °C using an electrochemical workstation. The in-depth analysis of the electrochemical performance of the ATO samples demonstrated their desirable capacitance behaviour, signifying the potential suitability of ATO nanostructures as electrode materials for supercapacitors. Notably, the highest capacitance value of 1064 F g⁻¹ was attained from the cyclic voltammetry (CV) curves at a scan rate of 2 mV s⁻¹ for the ATO nanoparticles prepared at 1100 °C. At a current density of 10 mA cm⁻², the ATO-based electrode exhibited an energy density of 21 W h kg⁻¹ and a power density of 390 W kg⁻¹, making it crucial for electrochemical devices. The outstanding capacitance retention of 90% was observed even after 3000 cycles in 3 M KOH electrolyte, in the potential window ranging from −0.2 to 0.55 V. The novel supercapacitor electrode in this study displayed an outstanding specific capacitance, exceptional stability, elevated power density, and reduced impedance, showcasing its promising practical utility. These encouraging results signify a pioneering approach for the synthesis of cost-effective ATO materials through an environmentally benign sol–gel process, paving the way for their prospective utilization in high-performance supercapacitors.