Emcoating Architecture Construction via CO /H Coupling Treatment Doubles Reversible Capacity of NbO /C Anode.

As a promising alternative as lithium-ion anode, niobium dioxide appeals to researchers due to high theoretical capacity and good electron conductivity. However, rarely work about NbO based high performance anode is reported. Here, NbO nanoparticles emcoated in continuous carbon matrix is constructed through CO /H coupling treatment. CO activation introduces unique carbon emcoating structure, which builds interconnected electron conductive network with low carbon content. Furthermore, crystallographic phase of NbO is enhanced during H treatment, which increases the lithium storage ability. Electrochemical performance of NbO anodes is significantly improved based on the carbon emcoating structure. A high reversible capacity of 391 mAh g is retained after 350 cycles at 0.2 C. Additionally, at a current density of 1 A g , the reversible capacity reaches 139 mAh g . Compared with conventional NbO /C nanohybrids, the lithium diffusion coefficient of carbon-emcoated sample shows improvement of three orders of magnitude. Moreover, the in situ XRD investigation shows a reversible lithium insertion behaviour with a limited volume change.