Song Wei, Zhao Hanqing, Ye Jianqi, Kang Mengmeng, Miao Siyu, Li Zhong
Key Laboratory of Coal Science and Technology of Ministry of Education and Shanxi Province, Institute of Coal Chemical Engineering , Taiyuan University of Technology , Taiyuan 030024 , Shanxi , China.
ACS Appl Mater Interfaces. 2019 May 15;11(19):17416-17424. doi: 10.1021/acsami.9b02123. Epub 2019 Apr 30.
Ti-O-C channels for ultrafast sodium storage were constructed in N/S-co-doped TiO-C nanofibers, which deliver a high rate performance of 181.9 mAh g at 5 A g after 3000 cycles. The existence of Ti-O-C bonds at the interface of TiO-C phases was revealed by synchrotron radiation X-ray absorption spectra. Based on this, first-principles calculations further verified the low energy barrier for Na insertion/extraction in the Ti-O-C channels formed by the intimately integrated graphite layer with TiO near the surface. In addition, surface defects induced by heteroatoms accelerate the Na mass transfer through the pathway from the carbon surface to the Ti-O-C channel.
在氮/硫共掺杂的TiO-C纳米纤维中构建了用于超快钠存储的Ti-O-C通道，该通道在3000次循环后，在5 A g的电流密度下具有181.9 mAh g的高倍率性能。同步辐射X射线吸收光谱揭示了TiO-C相界面处Ti-O-C键的存在。基于此，第一性原理计算进一步证实了在由靠近表面的TiO与紧密集成的石墨层形成的Ti-O-C通道中，钠嵌入/脱出的能量势垒较低。此外，杂原子诱导的表面缺陷加速了钠从碳表面到Ti-O-C通道的传质过程。
