Novel felt pseudocapacitor based on carbon nanotube/metal oxides

This work describes a novel supercapacitor electrode based on a glass fiber felt substrate, single-walled carbon nanotube (SWCNT) and metal oxide layers (RuO₂ or MnO₂). It is fabricated by the repeated and alternate deposition of SWCNTs and metal oxides via dipping and electrodeposition, respectively, to achieve three-dimensional layered hierarchical structured supercapacitor electrodes. The results show that the layered structured electrodes fabricated by alternating deposition of SWCNTs and metal oxides have higher capacitance as compared with the bulk deposited samples, which are fabricated by deposition of SWCNTs followed by metal oxides. The best configuration studied in this work shows specific capacitance of 72 and 98 F/g for the SWCNT–MnO₂ and SWCNT–RuO₂, respectively, whereas the corresponding areal capacitances are 0.07 and 0.09 F/cm². This three-dimensional porous electrode structure design combines the high mechanical stability of the felt substrate with the high conductivity and specific surface area of SWCNTs, and the high capacitance of metal oxides. This will add immensely to the research and development of wearable lightweight electronics in harsh environments.