Electronic Property Dependence of Electrochemical Performance for TiO2/CNT Core-shell Nanofibers in Lithium Ion Batteries

• DOI: 10.1016/j.electacta.2015.08.097
• Publication Date: 2015-08-21T22:56:48Z
• Authors: Rui Qing; Li Liu; Hansoo Kim; Wolfgang M. Sigmund
• Keywords: 7. Clean energy; 01 natural sciences; 0104 chemical sciences

Abstract TiO 2 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 Li 4 Ti 5 O 12 . However, the low intrinsic conductivity limits its electrochemical properties. In this paper, a sol-gel based route is presented to produce nanosize TiO 2 /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 TiO 2 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 TiO 2 nanofibers by both providing an alternative electron and lithium ion conducting mechanism as well as synergistic effects, which were systematically reviewed.