(Electrochemical Science and Technology Student Poster Winner) C-Doped TiO2-B Nanowires Derived from TiC As an Anode Materials for Lithium Ion Batteries with High Rate Performance
Among the anode materials, Titanium dioxide (TiO2) has been deeply investigated for lithium intercalation/de-intercalation due to high rate capability, very good reversible capacity, low volume expansion ( <2% ) upon cycling and furthermore lost cost, high abundant and very safe lithium reaction potential ~ 1.5 V vs Li/Li+, owing to these characteristics, TiO2 anodes have been considered to target in EVs and HEVs application1-3. Recently, the various polymorphs of TiO2 (anatase, rutle, brookite and bronze) have been explored as efficient anodes for LIB3. In particular, TiO2-Bronze (TiO2-B) has been receiving significant interest due to its theoretical capacity of 335 mAh g-1. Importantly, TiO2-B manifests the major advantages of fast charging-discharging through a pseudo-capacitive mechanism in addition to the bulk diffusion, whereas other polymorphs of TiO2 mostly show intercalation of Li-ion through bulk diffusion controlled mechanism3. However, the low electronic conductivity and low rate of Li-ion diffusivity of TiO2 are key issues for a high rate capable anode. To overcome these issues, we report synthesis of carbon-doped TiO2-B nanowires by facile and inexpensive method without using external carbon source. The carbon doping was verified by UV–visible and X-ray photoelectron spectroscopy and further structure and morphology was investigated with X-ray diffraction, Raman spectroscopy and Scanning and Transmission microscopies. The electrochemical performances of the C doped and undoped TiO2-B nanowires were tested by galvanostatic charge/discharge cycling, cyclic voltammetry, and electrochemical impedance spectroscopy. This novel C-doped materials presented high capacities and higher rate capability in electrochemical cycling experiments with respective to undoped material. This is attributed to the reduction of Li-ion diffusion path lengths along with improving electrical conductivity of TiO2-B nanowires. The electrochemical experiments demonstrated that C-TiO2-B nanowires electrodes exhibited superior lithium storage capacity of ~306 mAh g-1 at current rate of 0.1C as well as excellent rate ability of ~160 mAh g-1even at high current rate of 10C after 1000 cycle in lithium-ion batteries.
- S.Goriparti, E. Miele, F. D. Angelis, E.D. Fabrizio, R. P. Zaccaria, C. Capiglia, J. Power Sources, 257 (2014) 421
- G. Zhu, Y. G. Wang and Y. Y. Xia, Energy Environ. Sci., 5 (2012) 6652
- A. G. Dylla, G. Henkelman and K. J. Stevenson, Acc. Chem. Res, 46 (2013) 1104