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

• Published in: Electrochimica acta 2016-05, Vol.199, p.35-44
• Main Authors: Kim, Jinwoo, Kim, Ji Yoon, Pham-Cong, De, Jeong, Se Young, Chang, Jinho, Choi, Jun Hee, Braun, Paul V., Cho, Chae Ryong
• Format: Article
• Language: English
• Subjects: Carbon; carbon coating; Coating; diffusion coefficient; Double layer; graphene wrapping; lithium titanate; Lithium-ion batteries; Nanofibers; Rechargeable batteries; Titanates; Wrapping
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2016.03.137

[Display omitted] •Li4Ti5O12 nanofibers are fabricated by electrospinning and annealing process.•Carbon-coated Li4Ti5O12 nanofibers are prepared by hydrothermal process.•Individually graphene-oxide-wrapped Li4Ti5O12 nanofibers are prepared by electrostatic force.•Enhanced rate capability of carbon-coated and graphene-oxide-wrapped Li4Ti5O12 nanofibers. 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 (110mAhg−1at 20C) and over two orders of magnitude higher diffusion coefficient (DLi=∼1.04×10−11cm2s−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.