Superior Sodium Storage in Na2Ti3O7 Nanotube Arrays through Surface Engineering

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• 作者：Jiangfeng Ni ; Shidong Fu ; Chao Wu ; Yang Zhao ; Joachim Maier ; Yan Yu and Liang Li
• 刊名：Advanced Energy Materials
• 出版年：2016
• 出版时间：June 8, 2016
• 年：2016
• 卷：6
• 期：11
• 全文大小：889K
• ISSN：1614-6840

文摘

Sodium-ion batteries have attracted extraordinary attention owing to their low cost and raw materials in abundance. A major challenge of practical implementation is the lack of accessible and affordable anodes that can reversibly store a substantial amount of Na ions in a fast and stable manner. It is reported that surface engineered sodium titanate (Na₂Ti₃O₇) nanotube arrays directly grown on Ti substrates can serve as efficient anodes to meet those stringent requirements. The fabrication of the nanotube arrays involves hydrothermal growing of Na₂Ti₃O₇ nanotubes, surface deposition of a thin layer of TiO₂, and subsequent sulfidation. The resulting nanoarrays exhibit a high electrochemical Na-storage activity that outperforms other Na₂Ti₃O₇ based materials. They deliver high reversible capacities of 221 mAh g⁻¹ and exhibit a superior cycling efficiency and rate capability, retaining 78 mAh g⁻¹ at 10 C (1770 mA g⁻¹) over 10 000 continuous cycles. In addition, the full cell consisting of Na₂Ti₃O₇ nanotube anode and Na_2/3(Ni_1/3Mn_2/3)O₂ cathode is capable of delivering a specific energy of ≈110 Wh kg⁻¹ (based on the mass of both electrodes). The surface engineering can provide useful tools in the development of high performance anode materials with robust power and cyclability.