Single-walled carbon nanotubes as electrode materials for supercapacitors

Large-scale synthesized single-walled carbon nanotubes (SWNT) prepared by electric arc discharge method and a mixture of NiO and Y₂O ₃ as catalyst have been used as electrode materials for supercapacitors. N₂ adsorption/desorption measurement shows that the SWNT is a microporous and mesoporous material with specific surface area 435 m²•g^-1. The specific capacitance of the nitric acid treated SWNT in aqueous electrolyte reaches as high as 105 F/g, which is a combination of electric double layer capacitance and pseudocapacitance. The SWNT-based capacitors also have good charge/discharge reversibility and cycling perdurability.