High-Rate Long-Life Pored Nanoribbon VNbO Built by Interconnected Ultrafine Nanoparticles as Anode for Lithium-Ion Batteries.

VNbO is a novel lithium storage material, which has not been systematically investigated so far. Via electrospinning technology, VNbO samples with two different morphologies, pored nanoribbon and rodlike nanoparticles, are prepared in relatively low temperature and time-saving calcination conditions. It is found that the formation process of different morphologies depends on the control of self-aggregation of the precursor by using different sample collectors. Compared with rodlike VNbO (RL-VNbO), pored nanoribbon VNbO (PR-VNbO) can deliver a higher specific capacity, lower capacity loss, and better cyclability. Even cycled at 1000 mA g, the reversible capacity of 132.3 mAh g is maintained by PR-VNbO after 500 cycles, whereas RL-VNbO only exhibits a capacity of 102.7 mAh g. The enhancement should be attributed to the pored nanoribbon structure with large specific surface area and shorter pathway for lithium ions transport. Furthermore, the lithium ions insertion/extraction process is verified from refinement results of in situ X-ray diffraction data, which is associated with a lithium occupation process in type III and VI cavities through tunnels I, II, and III. In addition, high structural stability and electrochemical reversibility are also demonstrated. All of these advantages suggest that PR-VNbO is a promising anode material for lithium-ion batteries.