Electronic Property Dependence of Electrochemical Performance for TiO2/CNT Core-shell Nanofibers in Lithium Ion Batteries. (20th October 2015)

• Record Type: Journal Article
• Authors: Qing, Rui; Liu, Li; Kim, Hansoo; Sigmund, Wolfgang M.
• Is Part Of: Electrochimica acta. Volume 180(2015)
• Page Start: 295
• Page End: 306
• Publication Date: 2015-10-20
• Subjects: nanofiber -- TiO2 (Titania) -- CNT -- conductivity -- lithium ion battery; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2015.08.097
• Languages: English
• ISSNs: 0013-4686

Abstract

Graphical abstract: Highlights: TiO2 /CNT nanofibers with 126 nm diameter were prepared via electrospinning. CNT core-TiO2 shell structure were formed in the nanocomposite. CNT additive enhanced electronic conductivity and lithium diffusivity. Synergistic effect improves materials' electrochemical property in several ways. TiO2 anodes with near theoretical capacity and good rate performance were obtained. Abstract: TiO2 is one of the most promising anode candidates for novel lithium ion batteries which combines the advantage of state of art anode graphite and the safety of Li4 Ti5 O12 . However, the low intrinsic conductivity limits its electrochemical properties. In this paper, a sol-gel based route is presented to produce nanosize TiO2 /CNT core-shell composite fibers. Fiber diameter is 253 ± 63 nm as-spun and 126 ± 35 nm with subsequent calcination to obtain crystalline phase. Crystallite size is between 13–18 nm. The as-prepared core-shell fibers exhibited ∼1.5 time higher electronic conductivity, 1.6–3 times greater lithium diffusivity which resulted in 25% more galvanostatic capacity at C/10 compared to bare TiO2 nanofibers. The enhancement in high-rate performance at 10C was over 80% which was crucial for fast charging applications. CNT additives were found to enhance the electronic conductivity, lithium diffusivity and electrochemical properties of the TiO2 nanofibers by both providing an alternative electron and lithium ion conducting mechanism as well as synergistic effects, which were systematically reviewed.