Heteroatom-doped hollow carbon micro-tube derived from platanus catkins fiber for sodium ion supercapacitor

Abstract Heteroatom-doped hollow carbon micro-tubes are successfully fabricated from platanus catkins fibers by simply precarbonization and then KOH activation method for sodium ion supercapacitor. The different activation temperatures (600 °C, 700 °C and 800 °C) are used to study the effect on the structural and electrochemical performance of the bio-carbon materials. As the activation temperature increases, the disorder degrees and the surface (inner and outer) roughness of the as-prepared hollow carbon tubes (with diameters of about 15∼25 μm and a wall thickness around 2∼3 μm) increase. Benefiting from the proper numerous pores (micro-, meso- and macro-pores), high specific surface area, unique structure and heteroatom (N and O) dual doping, hollow carbon micro-tubes activated at 700 °C exhibit superior electrochemical performance with good rate capability and high specific capacity of 195, 140, 112, 95 and 84 mAh/g at the current densities of 0.1, 0.2, 0.5, 1 and 2 A/g, respectively.