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 SnO 2 nanospheres and V 2 O 5 /SnO 2 nanoparticles were obtained by a facile one-pot template method. The homogeneously distributed SnO 2 and V 2 O 5 /SnO 2 exhibit an optimized worm-like mesoporous skeleton and an ideal pore size distribution with a highest surface area of around 295.5 m 2 ·g −1 and 198.0 m 2 ·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 V 2 O 5 /SnO 2 @CFT as the positive electrode and SnO 2 @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.