Nitrogen-doped carbon nanotubes as cathode for lithium–air batteries

Nitrogen-doped carbon nanotubes (N-CNTs) were synthesized by a floating catalyst chemical vapor deposition (FCCVD) method. Various techniques including X-ray photoelectron spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Raman spectroscopy revealed the morphology and structure of CNTs and N-CNTs as well confirmed the existence of incorporated nitrogen (10.2 at.%) in N-CNTs. N-CNTs were investigated as cathode material for lithium–air batteries and exhibited a specific discharge capacity of 866 mAh g− 1, which was about 1.5 times as that of CNTs. Our results indicated that the N-CNTs electrode showed high electrocatalytic activities for the cathode reaction thus improving the lithium–air battery performance.

Research highlights
► CNTs and N-CNTs as cathode materials were studied in lithium–air batteries.
► N-CNTs delivered 1.5 times discharge capacity as that of CNTs.
► N-CNTs showed improvement to the reversibility.
► The performance improvement of N-CNTs results from heteroatom nitrogen doping.