SnO2 nanospheres and V2O5/SnO2 nanoparticles with mesoporous structures for flexible asymmetric supercapacitors

Carbon fibers’ textile (CFT)-based flexible electrodes containing a large number of SnO2 nanospheres and V2O5/SnO2 nanoparticles were obtained by a facile one-pot template method. The homogeneously distributed SnO2 and V2O5/SnO2 exhibit an optimized worm-like mesoporous skeleton and an ideal pore size distribution with a highest surface area of around 295.5 m2·g−1 and 198.0 m2·g−1, respectively. Using the mesoporous transition/mixed transition metal oxide nanomaterials simultaneously as both positive and negative electrodes, a solid-state flexible asymmetric supercapacitor was fabricated with the V2O5/SnO2@CFT as the positive electrode and SnO2@CFT as the negative electrode with well-widened voltage windows. Benefiting from the 3D controllable mesoporous architecture of electroactive species, the assembled supercapacitors delivered a high specific capacitance of 151.3 F·g−1 at 1 A·g−1, and good rate stability with 70.9% capacitance retention at a higher current density of 5 A·g−1. Notably, the device can operate in a wide voltage window (0~1.6 V), which enhance substantially the energy density to 193.6 Wh·kg−1 at a power density of 2880 W·kg−1. These encouraging results are expected to open up a possibility of designing and fabricating the other metal oxide nanomaterials with mesoporous structure and uniform morphology for high-performance supercapacitors and other energy storage devices application.