Nitrogen-Doped Carbon\nNanotube/Graphite Felts as Advanced\nElectrode Materials for Vanadium Redox Flow Batteries

Abstract

Nitrogen-doped carbon nanotubes have been grown, for\nthe first\ntime, on graphite felt (N-CNT/GF) by a chemical vapor deposition approach\nand examined as an advanced electrode for vanadium redox flow batteries\n(VRFBs). The unique porous structure and nitrogen doping of N-CNT/GF\nwith increased surface area enhances the battery performance significantly.\nThe enriched porous structure of N-CNTs on graphite felt could potentially\nfacilitate the diffusion of electrolyte, while the N-doping could\nsignificantly contribute to the enhanced electrode performance. Specifically,\nthe N-doping (i) modifies the electronic properties of CNT and thereby\nalters the chemisorption characteristics of the vanadium ions, (ii)\ngenerates defect sites that are electrochemically more active, (iii)\nincreases the oxygen species on CNT surface, which is a key factor\ninfluencing the VRFB performance, and (iv) makes the N-CNT electrochemically\nmore accessible than the CNT.