Zn-doped SnO₂ nano-urchin-enriched 3D carbonaceous framework for supercapacitor application

Hierarchical Zn-doped SnO₂ nano-urchins decorated on RGO nanosheets were fabricated for supercapacitor applications. In this study, SnO₂ nanospheres were doped with Zn²⁺ to tailor their electrical and morphological properties. Zn²⁺ doping of the SnO₂ nanospheres prevented Sn clustering and thereby reduced the particle size leading to the formation of urchin-like nanostructures. These urchins with a high surface area and short transport paths can offer high capacitive performance by assembling with RGO nanosheets. The X-ray photoelectron spectroscopy and X-ray diffraction analyses confirmed the presence of SnO₂ crystal planes and successful doping of the Zn²⁺. The incorporation of the RGO nanosheets augmented the coulombic efficiency, specific capacitance, and cycling performance. The enhancement of the capacitive behavior resulted from the synergistic effects owing to the combined properties of pseudocapacitance and double layer capacitance. The composite electrode material offered a specific capacitance of 635 F g^-1 at a current density of 1 A g^-1 and has a high cycling stability up to 5000 cycles with a capacitance retention of 78.4%.