Self-Improving Anode for Lithium-Ion Batteries Based on Amorphous to Cubic Phase Transition in TiO2 Nanotubes

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• 作者：Hui Xiong ; Handan Yildirim ; Elena V. Shevchenko ; Vitali B. Prakapenka ; Bonil Koo ; Michael D. Slater ; Mahalingam Balasubramanian ; Subramanian K. R. S. Sankaranarayanan ; Jeffrey P. Greeley ; Sanja Tepavcevic ; Nada M. Dimitrijevic ; Paul Podsiadlo ; Christopher S. Johnson ; Tijana Rajh
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：February 2, 2012
• 年：2012
• 卷：116
• 期：4
• 页码：3181-3187
• 全文大小：1021K
• 年卷期：v.116,no.4(February 2, 2012)
• ISSN：1932-7455

文摘

We report an electrochemically driven transformation of amorphous TiO₂ nanotubes for Li-ion battery anodes into a face-centered-cubic crystalline phase that self-improves as the cycling proceeds. The intercalation/deintercalation processes of Li ions in the electrochemically grown TiO₂ nanotubes were studied by synchrotron X-ray diffraction and absorption spectroscopies along with advanced computational methods. These techniques confirm spontaneous development of a long-range order in amorphous TiO₂ in the presence of high concentration of Li ions (>75%). The adopted cubic structure shows long-term reversibility, enhanced power with capacity approaching the stochiometry of Li₂Ti₂O₄. The anode shows also superior stability over 600 cycles and exhibits high specific energy (200 W h kg_electrode^鈥?) delivered at a specific power of 30 kW kg_electrode^鈥?. The TiO₂ anode in a full Li-ion cell with a LiNi_0.5Mn_1.5O₄ cathode operates at 2.8 V and demonstrates the highest (310 mA h/g) reversible specific capacity reported to date. Our conceptually new approach fosters the ability of amorphous nanoscale electrodes to maximize their capacity in operando, opening a new avenue for synthesis of safe and durable high-power/high-capacity batteries.