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 mu m, 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). (C) 2016 Elsevier B.V. All rights reserved.