Interfacial engineering of 1D SnO2@WO3 heterojunction nanofibers toward high-performance pseudocapacitive energy storage

The SnO 2 /WO 3 nanoparticle-decorated heterojunction ensures electron and ion exchange. • Decorated WO 3 nanoparticles effectively suppress the volume expansion of SnO 2 . • This heterostructure exposes abundant active sites for faradaic redox reactions. • Synergistic effects enable specific capacitance of 238.3 F g −1 at 1 A g −1 . • Interfacial interactions maintain structural integrity with 91.2% stability. One-dimensional (1D) metal oxide nanomaterials attract increasing interest for supercapacitor applications. Therefore, the rational design and facile construction of unique 1D heterostructures remain highly desirable for advanced energy storage. Herein, a novel architecture comprising 1D SnO 2 nanofibers (NFs) uniformly decorated with 0D WO 3 nanoparticles (NPs) is successfully fabricated via coaxial electrospinning coupled with subsequent thermal calcination. By finely tuning the molar ratio of the respective precursors, the loading density of the WO 3 NPs on the SnO 2 skeleton is precisely modulated. This distinctive 1D/0D heterostructure effectively exposes abundant electroactive sites and significantly augments the interfacial contact area with the electrolyte, synergistically boosting the electrochemical kinetics. Consequently, at an optimal WO 3 -to-SnO 2 molar ratio of 1:1, the assembled SWHNC-2 electrode delivers a specific capacitance of 238.3 F g −1 at 1 A g −1 . It also exhibits suitable rate capability (retaining 56.7% capacitance at 10 A g −1 ) and moderate cycling stability (91.2% capacitance retention over 2000 cycles at 5 A g −1 ). Moreover, a symmetric supercapacitor assembled from this composite achieves maximum energy density of 4.64 Wh kg −1 at a power density of 448 W kg −1 , while maintaining 78% of its initial capacitance after 1000 cycles, indicating its preliminary potential for energy storage. These findings unequivocally highlight the rationally engineered SnO 2 @WO 3 composite as a promising electrode candidate for next-generation supercapacitors. Download: Download high-res image (413KB) Download: Download full-size image