Porous graphitic carbon microtubes derived from willow catkins as a substrate of MnO2 for supercapacitors

摘要

Biomass is receiving considerable attention because of its significant advantages as a sustainable and renewable material. Willow catkins, which have a single-walled microtubular structure are used as both a template and a precursor for synthesizing porous graphitic carbon microtubes (PGCMT) induced by the simultaneous activation-graphitization of K4Fe(CN)(6). In addition to providing low-resistant pathways and short ion diffusion channels, as-obtained PGCMT with tubular structure also serves as an ideal platform for anchoring MnO2. The PGCMT/MnO2 composite electrode obtained by MnO2 electrodeposition expressed excellent electrochemical performance, including a significantly enhanced specific capacitance (550.8 F g(-1) for the mass of MnO2 at a current density of 2 A g-1), a high capacitance retention of 61.8% even at a high current density of 50 A g(-1), and an excellent cycling stability of 89.6% capability retention after 5000 cycles. These findings offer a simple and environmentally friendly strategy for preparing advanced energy materials by utilizing the unique structure of biomass waste from nature. (C) 2017 Elsevier B.V. All rights reserved.