Black Anatase Titania with Ultrafast Sodium-Storage Performances Stimulated by Oxygen Vacancies

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• 作者：Jun Chen ; Zhiying Ding ; Chao Wang ; Hongshuai Hou ; Yan Zhang ; Chiwei Wang ; Guoqiang Zou ; Xiaobo Ji
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：April 13, 2016
• 年：2016
• 卷：8
• 期：14
• 页码：9142-9151
• 全文大小：699K
• 年卷期：0
• ISSN：1944-8252

文摘

Nanostructured black anatase titania with oxygen vacancies (OVs) is efficiently obtained and employed as an anode in sodium-ion batteries (SIBs) for the first time. The incorporation of OVs into TiO₂ is demonstrated to render considerably enhanced-rate performances, higher initial capacities, and an accelerated electrochemical activation process during cycling, derived from the boosted intrinsic electric conductivity and improved kinetics of Na uptake. Bestowed with the integrated merits of OVs and shortened Na ion diffusion length in the nanostructure, black titania delivers a reversible specific capacity of 207.6 mAh g^–1 at 0.2 C, retains 99.1% over 500 cycles at 1 C stably, and still maintains 91.2 mAh g^–1 even at the high rate of 20 C. Density functional theory (DFT) calculations suggest that the lower sodiation energy barrier of anatase with OVs enables a more favorable Na intercalation into black anatase. Thus, it is of great significance to introduce OVs into TiO₂ to stimulate ultrafast and durable sodium-storage properties, which also offers a potential strategy to project more superior electrodes, utilizing internal defects.