Quinone-decorated onion-like carbon/carbon fiber hybrid electrodes for high-rate supercapacitor applications

The energy performance of carbon onions can be significantly enhanced by introducing pseudocapacitive materials, but this is commonly at the cost of power handling. In this study, a novel synergistic electrode preparation method was developed by using carbon-fiber substrates loaded with quinone-decorated carbon onions. The electrodes are free standing, binder free, extremely conductive, and the interfiber space filling overcomes the severely low apparent density commonly found for electrospun fibers. Electrochemical measurements were performed in organic and aqueous electrolytes. For both systems, a high electrochemical stability after 10 000 cycles was measured, as well as a long-term voltage floating test for the organic electrolyte. The capacitance in 1 M H2SO4was 288 F g−1for the highest loading of quinones, which is similar to literature values, but with a very high power handling, showing more than 100 F g−1at a scan rate of 2 Vs−1.