Bio-inspired hollow activated carbon microtubes derived from willow catkins for supercapacitors with high volumetric performance.

A novel bio-inspired hollow activated carbon microtubes (HACMs) was prepared from low-cost, renewable biomass willow catkins by low temperature pre-carbonization combined with KOH chemical activation and used as supercapacitor electrode materials. The as-prepared HACMs exhibit hollow fiber-like structure with thin wall thickness of less than 1 µm, high microporosity surface area (997 m 2 g −1 ) and concentrated pore size distribution (1–2 nm). The electrochemical measurement results demonstrate that the HACMs electrode materials have high gravimetric capacitance of 306 F g −1 superior to most of the previously reported activated carbons and outstanding volumetric capacitance of 303 F cm −3 . [ABSTRACT FROM AUTHOR]