Individually carbon-coated and electrostatic-force-derived graphene-oxide-wrapped lithium titanium oxide nanofibers as anode material for lithium-ion batteries

摘要

The as-electrospun polymeric lithium titanate nanofibers are crystallized into Li4Ti5O12 nanofibers (denoted as LTO NFs) via post-annealing. The LTO NFs are coated with a carbon layer using a glucose polymer via hydrothermal synthesis. The GO layer electrostatically attracts to the positively charged LTO NFs, resulting in the uniform wrapping of individual LTO NFs without aggregation. The introduction of uniformly coated carbon and GO double layers led to an enhanced rate capability (110 mAh g (1) at 20C) and over two orders of magnitude higher diffusion coefficient (D-Li = similar to 1.04 x 10 (11) cm(2) s (1)) of the tailored LTO NFs with carbon and GO network compared with those of the pristine LTO NFs. Extended testing for over 100 cycles demonstrates the cyclic stability and Coulombic efficiency of over 99% of this system. These results indicate that the interconnection and networks of LTO NFs through carbon coating and the individual GO wrapping, which facilitates the lithium ion and electron transportation, may show excellent electrochemical performance. (C) 2016 Elsevier Ltd. All rights reserved.