High cyclability of ionic liquid-produced TiO₂ nanotube arrays as an anode material for lithium-ion batteries

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• 作者：Huaqing Li ; Surendra K. Martha ; Raymond R. Unocic ; Huimin Luo ; Sheng Dai ; Jun Qu
• 关键词：TiO2 nanotubes ; Ionic liquids ; Lithium-ion battery ; Anode ; Cyclability
• 刊名：Journal of Power Sources
• 出版年：2012
• 出版时间：15 November, 2012
• 年：2012
• 卷：218
• 期：Complete
• 页码：88-92
• 全文大小：1069 K

文摘

TiO₂ 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 TiO₂ 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 TiO₂ 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 TiO₂ matrix (organic cations repelled away). Promising electrochemical results have been achieved when using the IL-produced TiO₂ 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.