Porous nitrogen and oxygen co-doped carbon microtubes derived from plane tree fruit fluff for high-performance supercapacitors

Porous nitrogen and oxygen co-doped carbon microtubes (PCMTs) were prepared via carbonization followed by activation of plane tree fruit fluffs (PTFFs) and employed as high-performance supercapacitor electrode materials. The pore structures, surface chemistry and degree of graphitization of the final products can be facilely tailored by adjusting the activation temperature, which changed remarkably as the activation temperature increased from 650 to 900 °C. The PCMT-850 obtained by activating at 850 °C possessed despite the second largest specific surface area (1533 m2/g), but the highest mesopore ratio (9.13%), the maximal nitrogen content (2.20 at.%) and highest degree of graphitization as well as excellent electrical conductivity. The PCMT-850-based carbon electrode exhibited the highest charge storage capacity with a specific capacitance of 257.6 F/g at a current of 1 A/g and the lowest internal resistance in 6 M KOH. The high supercapacitor performance can be attributed to the combined effects of its pore structure, heteroatom doping effects and degree of crystallinity. The favorable capacitive performance render the waste biomass PTFFs serve as novel resources of nitrogen and oxygen co-doped carbon materials for high-performance supercapacitors.