The synergistic effect of the RuO 2 nanoparticle-decorated V 2 O 5 heterostructure for high-performance asymmetric supercapacitors

Two-dimensional RuO 2 nanoparticle-decorated V 2 O 5 nanoflakes are successfully synthesized by a simple solvothermal method. The synthesized RuO 2 -decorated V 2 O 5 nanocomposite electrode exhibited a high charge–discharge capacity with an excellent cyclic retention of 94.6% over 10 000 cycles. Specifically, the 3 wt% RuO 2 in V 2 O 5 (R2) nanocomposite electrode showed a high specific capacitance of 421 F g −1 at a current density of 1 A g −1 in a three-electrode system. The specific capacitance of the R2 nanocomposite is almost 3-fold higher than that of pure V 2 O 5 nanosheets in the three-electrode system. An energy density of 29 Wh kg −1 was achieved in a two-electrode system at a power density of 816 W kg −1 in an R2 based asymmetric supercapacitor device. The energy density and power density of the RuO 2 –V 2 O 5 nanocomposite are higher than those of previously reported V 2 O 5 nanostructured asymmetric supercapacitors.