Synergistic effect of heterointerface engineering and oxygen vacancy in electro-spun polymer fibres derived carbon-supported 1D hierarchical WO3/SnO2 nanostructures for high-performance supercapacitor devices

Abstract

Herein, we report the fabrication of a high-performance supercapacitor device via nanoscale integration of bimetallic oxide nanocomposites with modulated electronic and interfacial effects. The 1D hierarchical architecture consisting of carbon fibers supported WO₃/SnO₂ nanostructures is synthesized via an efficient and scalable strategy of single-spinneret electrospinning followed by controlled calcination. The fabricated supercapacitive electrode material (WO₃/SnO₂@C) offers higher pseudocapacitive performance and durability than its counterparts, viz., WO₃ and SnO₂. The detailed physicochemical (ex situ XPS, FTIR, and Raman) and electrochemical characterization of the fabricated samples suggest that the improved conductivity and lowered charge transfer resistance due to cooperative effects between the surface defects (like oxygen vacancies) and the hetero-interfacial effects are responsible for the enhanced device performance. The specific capacitance of 589 F g⁻¹ at 6 A g⁻¹ and an enhanced coulombic efficiency with capacity retention of ∼80% after 5000 charging–discharging cycles depicting longer durability were noted for the half-cell configuration. Importantly, a flexible all-solid-state symmetric device (full-cell configuration) demonstrates an energy density of 1800 mW h kg⁻¹, a power density of 2400 W kg⁻¹, the gravimetric capacitance of 20 F g⁻¹ at 0.5 A g⁻¹ for an extended working voltage window of 1.2 V, and 100% durability (at least till 1000 cycles).