Anatase TiO2: Better Anode Material Than Amorphous and Rutile Phases of TiO2 for Na-Ion Batteries

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• 作者：Dawei Su ; Shixue Dou ; Guoxiu Wang
• 刊名：Chemistry of Materials
• 出版年：2015
• 出版时间：September 8, 2015
• 年：2015
• 卷：27
• 期：17
• 页码：6022-6029
• 全文大小：583K
• ISSN：1520-5002

文摘

Amorphous TiO₂@C nanospheres were synthesized via a template approach. After being sintered under different conditions, two types of polyphase TiO₂ hollow nanospheres were obtained. The electrochemical properties of the amorphous TiO₂ nanospheres and the TiO₂ hollow nanospheres with different phases were characterized as anodes for the Na-ion batteries. It was found that all the samples demonstrated excellent cyclability, which was sustainable for hundreds of cycles with little capacity fading, although the anatase TiO₂ presented a capability that was better than that of the mixed anatase/rutile TiO₂ or the amorphous TiO₂@C. Through crystallographic analysis, it was revealed that the anatase TiO₂ crystal structure supplies two-dimensional diffusion paths for Na-ion intercalation and more accommodation sites. Density functional theory calculations indicated lower energy barriers for the insertion of Na⁺ into anatase TiO₂. Therefore, anatase TiO₂ hollow nanospheres show excellent high-rate performance. Through ex situ field emission scanning electron microscopy, it was revealed that the TiO₂ hollow nanosphere architecture can be maintained for hundreds of cycles, which is the main reason for its superior cyclability.