Facile fabrication of carbon microtube arrays from waste wood for use as self-supporting supercapacitor electrodes

Porous biomass-based carbon materials with microtube arrays have been fabricated from larch waste wood by coupling green delignification and multistage carbonization. The microtube structure and pore size of the sample were effectively controlled by multistage carbonization. The obtained sample possessed a stable self-supporting microtube array structure with well-defined porosity (surface area of 945.09 m(2) g(-1)) and an ideal proportion of micropores (88%). Owing to the specific porous structure and stable self-supporting system, the material showed excellent supercapacitor electrochemical performance. Remarkably, the material showed high specific capacitance (211.3 F g(-1) and 58.3 F cm(-3)), energy density (105.6 W h kg(-1)), power density (900.0 W kg(-1)), and stability (70% after 9000 cycles). Additionally, the obtained alkali activation sample, M-CMAk-800, demonstrates a splendid specific capacitance of 408.5 F g(-1) at a current density of 0. 5 A g(-1), a great rate capability retention (69%), and outstanding stability (100% after 4000 cycles) due to its high specific surface area (up to 1689.4 m(2) g(-1)) and large total pore volume (up to 1.17 cm(3) g(-1)). This work realizes efficient utilization and conversion of waste wood by green delignification and a multistage carbonization process, and will open a new avenue for preparing high chemical performance self-supporting supercapacitor electrodes from biomass waste.