Amorphous RuO2 coated on carbon spheres as excellent electrode materials for supercapacitors
Significant enhancement in supercapacitor performances was achieved by the first fabrication of amorphous RuO2 hybrid by utilising carbon spheres as templates. The as-prepared carbon spheres (Cs)/RuO2 and reduced carbon spheres (rCs)/RuO2 composites exhibit high specific capacitances of 387 F g−1 (44.2 wt% RuO2 loading) and 614 F g−1 (72.6 wt% RuO2 loading) at a current density of 1 A g−1 at 2 mg cm−2 loading mass, showing remarkable rate capability with capacitances of 336 F g−1 and 491 F g−1 at a current density of 20 A g−1 and excellent cycling stability with capacity retention of 97.7% and 90.8% for 5000 cycles. The enhanced electrochemical performances could be attributed to the unique structure of the resulted composites as well as the high utilization of well-dispersed RuO2 nanoparticles on the carbon surface. These results demonstrate the great potential of carbon sphere-based composites in the development of high-performance electrode materials for supercapacitors.