Temperature-driven enhancement in pseudocapacitive charge storage of Sn-doped WO₃ nanoflowers and its high-performance quasi-solid-state asymmetric supercapacitor

The substitution of another metal cations in the WO₃ matrix enhances their electrochemical performance due to the synergistic effect. In this report, Sn-doped WO₃ nanoflowers are synthesized via a facile single-step hydrothermal method. Further, the temperature-dependent pseudocapacitive behavior of Sn-doped WO₃ nanoflowers is investigated for quasi-solid state asymmetric supercapacitors (QSSAC). The electrochemical study reveals that the specific capacitance values of WO₃ increase from 72 F g⁻¹ to 138 F g⁻¹ (Sn-doped WO₃) at 1 A g⁻¹. The temperature-dependent specific capacitance values of Sn-doped WO₃ nanoflowers demonstrating six times enhancement with rising temperature, from 109 F g⁻¹, 139 F g⁻¹, 194 F g⁻¹, 301 F g⁻¹, to 603 F g⁻¹ at 10 °C, 20 °C, 30 °C, 40 °C, to 50 °C respectively. Furthermore, the QSSAC exhibits better stability of 97.51 % up to 2500th cycles with an energy density of 8 W h kg⁻¹ and a power density of 6400 W kg⁻¹, attributed to enhanced conductivity, large diffusion capability, and high strength with multiple redox active sites. The experimental results emphasize the promising electrochemical features of the Sn-doped WO₃ matrix, which is an effective approach for electrode materials development.