Abstract
TiO 2 nanotubes (NTs) are considered as a potential SEI-free anode material for Li-ion batteries to offer enhanced safety. Organic solutions, dominatingly ethylene glycol (EG)-based, have widely been used for synthesizing TiO 2 NTs via anodization because of their ability to generate long tubes and well-aligned structures. However, it has been revealed that the EG-produced NTs are composited with carbonaceous decomposition products of EG, release of which during the tube crystallization process inevitably causes nano-scale porosity and cracks. These microstructural defects significantly deteriorate the NTs' charge transport efficiency and mechanical strength/toughness. Here we report using ionic liquids (ILs) to anodize titanium to grow low-defect TiO 2 NTs by reducing the electrolyte decomposition rate (less IR drop due to higher electrical conductivity) as well as the chance of the decomposition products mixing into the TiO 2 matrix (organic cations repelled away). Promising electrochemical results have been achieved when using the IL-produced TiO 2 NTs as an anode for Li-ion batteries. The ILNTs demonstrated excellent capacity retention without microstructural damage for nearly 1200 cycles of charge-discharge, while the NTs grown in a conventional EG solution totally pulverized in cycling, resulting in significant capacity fade.
Original language | English |
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Pages (from-to) | 88-92 |
Number of pages | 5 |
Journal | Journal of Power Sources |
Volume | 218 |
DOIs | |
State | Published - Nov 15 2012 |
Funding
The authors thank Drs. Nancy J. Dudney and Jagjit Nanda from Oak Ridge National Laboratory for technical discussion and facility support. Research is sponsored by the US Department of Energy, EERE Industrial Materials Program , under the American Recovery and Reinvestment Act. The characterization work was supported in part by ORNL's SHaRE User Facility, which is sponsored by the DOE Office of Basic Energy Sciences .
Keywords
- Anode
- Cyclability
- Ionic liquids
- Lithium-ion battery
- TiO nanotubes