He Yitao, Fan Wenda, Zhang Yaohui, Wang Zhihong, Li Xifei, Liu Zhiguo, Lü Zhe
School of Physics, Harbin Institute of Technology, No. 92, Xidazhi Street, Harbin, Heilongjiang 150001, China.
Xi'an Key Laboratory of New Energy Materials and Devices, Institute of Advanced Electrochemical Energy, School of Materials Science and Engineering, Xi'an University of Technology, Xi'an, Shaanxi 710048, PR China.
ACS Appl Mater Interfaces. 2020 May 13;12(19):22268-22277. doi: 10.1021/acsami.0c00789. Epub 2020 Apr 30.
Traditionally, dendrite growth is considered to be one of the reasons leading to poor performance of lithium metal. However, it is found that the growth of dendrites does not necessarily reduce the Coulombic efficiency (CE) of lithium metal. Here, the relationships among morphologies, solid electrolyte interphase (SEI) composition, and the CE of lithium metal have been systematically studied. By comparing different kinds of morphologies of lithium metal and the electrolytes, we discovered that SEI composition showed a great influence on the CE of lithium metal owing to the enhanced desolvation of the SEI by ionic compounds such as lithium fluoride and lithium nitride. In addition, we further developed a new method using electrochemical impedance spectroscopy of the symmetric Li-Li cell to study the properties of the SEI.
传统上，枝晶生长被认为是导致锂金属性能不佳的原因之一。然而，发现枝晶的生长不一定会降低锂金属的库仑效率（CE）。在此，系统地研究了锂金属的形态、固体电解质界面（SEI）组成与CE之间的关系。通过比较锂金属和电解质的不同形态，我们发现由于诸如氟化锂和氮化锂等离子化合物增强了SEI的去溶剂化作用，SEI组成对锂金属的CE有很大影响。此外，我们进一步开发了一种利用对称Li-Li电池的电化学阻抗谱来研究SEI性质的新方法。
