Dong Ruiqi, Zheng Lumin, Bai Ying, Ni Qiao, Li Yu, Wu Feng, Ren Haixia, Wu Chuan
Beijing Key Laboratory of Environmental Science and Engineering, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing, 100081, China.
Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing, 314019, China.
Adv Mater. 2021 Sep;33(36):e2008810. doi: 10.1002/adma.202008810. Epub 2021 Jul 30.
The sodium storage performance of a hard carbon (HC) anode in ether electrolytes exhibits a higher initial Coulombic efficiency (ICE) and better rate performance compared to conventional ester electrolytes. However, the mechanism behind faster Na storage kinetics for HC in ether electrolytes remains unclear. Herein, a unique solvated Na and Na co-intercalation mechanism in ether electrolytes is reported using designed monodispersed HC nanospheres. In addition, a thin solid electrolyte interphase film with a high inorganic proportion formed in an ether electrolyte is visualized by cryo transmission electron microscopy and depth-profiling X-ray photoelectron spectroscopy, which facilitates Na transportation, and results in a high ICE. Furthermore, the fast solvated Na diffusion kinetics in ether electrolytes are also revealed via molecular dynamics simulation. Owing to the contribution of the ether electrolytes, an excellent rate performance (214 mAh g at 10 A g with an ultrahigh plateau capacity of 120 mAh g ) and a high ICE (84.93% at 1 A g ) are observed in a half cell; in a full cell, an attractive specific capacity of 110.3 mAh g is achieved after 1000 cycles at 1 A g .
与传统酯类电解质相比，硬碳（HC）负极在醚类电解质中的钠存储性能表现出更高的初始库仑效率（ICE）和更好的倍率性能。然而，醚类电解质中HC更快的钠存储动力学背后的机制仍不清楚。在此，使用设计的单分散HC纳米球报道了醚类电解质中独特的溶剂化Na和Na共嵌入机制。此外，通过低温透射电子显微镜和深度剖析X射线光电子能谱观察到在醚类电解质中形成的具有高无机比例的薄固体电解质界面膜，这有利于Na传输，并导致高ICE。此外，还通过分子动力学模拟揭示了醚类电解质中快速的溶剂化Na扩散动力学。由于醚类电解质的作用，在半电池中观察到优异的倍率性能（在10 A g下为214 mAh g，具有120 mAh g的超高平台容量）和高ICE（在1 A g下为84.93%）；在全电池中，在1 A g下循环1000次后实现了110.3 mAh g的有吸引力的比容量。
