Nitrogen-doped carbon nanotubes with hydrazine treatment as cathode materials for lithium-oxygen batteries

Nitrogen-doped multi-wall carbon nanotubes (N-MWCNTs) were obtained by hydrazine reflux treatment. The introduction of hydrazine leads to successful nitrogen insertion in the form of mostly pyrrolic N. Meanwhile, the intrinsic characteristics of carbon nanotubes were retained. In addition, the N-MWCNTs exhibited superior electrochemical performance to that of pristine multi-wall carbon nanotubes (MWCNTs). The prepared N-MWCNTs delivered an initial discharge capacity of 2,927 mAh g(-1) at a current density of 0.05 mA cm(-2) and presented better reversibility especially at high rate and better electrocatalytic activity than MWCNTs. The results revealed that nitrogen doping into MWCNTs facilitated the reduction of oxygen and it was beneficial for Li2O2 decomposition as well.