Nitrogen and oxygen dual-doped carbon nanohorn for electrochemical capacitors

Single-walled carbon nanohorn (CNH) has a unique structure of high electrical conductivity, which makes it potentially utilizing in energy storage. However, it is hardly used as supercapacitor alone due to enclosing internal structure and lack of faradic active sites. Here, we demonstrate the fabrication of nitrogen and oxygen dual-doped carbon nanohorn (N:CNH) via a facile arc-discharge method and subsequent nitriding treatment. The nanohorn with the dopant has better hydrophilia and larger specific surface area than pure nanohorn. The N:CNH shows a great specific capacitance of 240 F g−1 at the current density of 0.5 A g−1 in 1 M H2SO4 with three-electrode configuration and 44 F g−1 at the current density of 0.5 A g−1 as coin cell. The capacitance of N:CNH attributes to the contribution of pseudocapacitance due to the N,O dual-doping. Moreover, its outstanding durability exhibits no obvious attenuation for 10,000 cycles. The specific energy density of 34.8 W h kg−1 for N:CHN at the current density of 0.5 A g−1 in Li2SO4 awards it qualification as a promising candidate in the future.

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