Electrospun Hierarchical Li₄Ti_4.95Nb_0.05O₁₂/Carbon Composite Nanofibers for High Rate Lithium Ion Batteries

One-dimensional (1D) Li 4 Ti 5 O 12 /C and Li 4 Ti 4.95 Nb 0.05 O 12 /C composite nanofibers with diameter of approximately 200 nm and length up to several micrometers were synthesized by using electrospinning method combined with thermal treatment in argon. Field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and thermogravimetric analysis were performed to characterize their morphologies and structures. The results revealed that the Li 4 Ti 4.95 Nb 0.05 O 12 /C nanofibers consisted of many nano-sized particles with the diameter of 30 ∼ 40 nm. Both the transition of a certain amount of Ti 4+ to Ti 3+ as charge compensation with the doping of niobium, uniform carbon coating on the surface and throughout the interior of each secondary nanoparticles, give rise to excellent electronic conductivity for Li 4 Ti 4.95 Nb 0.05 O 12 /C and hence greatly improve its rate capability.