Zhang Nan, Ding Fei, Yu Shihui, Zhu Kongying, Li Huan, Zhang Weiguo, Liu Xingjiang, Xu Qiang
National Key Laboratory of Science and Technology on Power Sources , Tianjin Institute of Power Sources , Tianjin 300384 , P. R. China.
School of Chemical Engineering , The University of Adelaide , Adelaide 5005 , South Australia.
ACS Appl Mater Interfaces. 2019 Aug 7;11(31):27897-27905. doi: 10.1021/acsami.9b08218. Epub 2019 Jul 24.
Owing to the expanding function of Li-ion transmission channels, it is important to explore the doping effects of different compounds into sulfide solid electrolytes to improve their electrochemical performances. However, it is hard to characterize the doping behaviors within sulfide solid electrolytes with low crystallinity and poor stability just by conventional crystallography analytical methods. In this work, the dielectric spectrum testing combined with other analytical methods, such as Li solid-state nuclear magnetic resonance, X-ray photoelectron spectroscopy, and the electrochemical method, have been applied to investigate the dual-doping behaviors of WS and LiBr within LiPS glass-ceramic electrolytes. This research method can not only evaluate the internal acting effect between the skeleton of sulfide solid electrolytes and the migrating kinetics of Li ions but also explore the capacitance at the interfaces of LiCoO/sulfide solid electrolytes. The experimental results show that the number of Li ions with fast transport velocity within LiS-PS-based solid electrolytes has been increased. Meanwhile, the interfacial capacitances between LiS-PS-based solid electrolytes and the LiCoO cathode have decreased after dual-doping of WS and LiBr, indicating a synergetic effect for the doped LiPS glass-ceramic electrolytes in terms of the ionic conductivities and interfacial compatibilities. This work may provide a novel analytical approach to explore both the diffusion kinetics and interfacial behaviors for the solid electrolytes of lithium batteries.
由于锂离子传输通道功能的扩展，探索不同化合物对硫化物固体电解质的掺杂效应以改善其电化学性能具有重要意义。然而，仅通过传统的晶体学分析方法很难表征结晶度低且稳定性差的硫化物固体电解质中的掺杂行为。在这项工作中，介电谱测试与其他分析方法相结合，如锂固体核磁共振、X射线光电子能谱和电化学方法，已被用于研究WS和LiBr在LiPS玻璃陶瓷电解质中的双掺杂行为。这种研究方法不仅可以评估硫化物固体电解质骨架与锂离子迁移动力学之间的内部作用效果，还可以探索LiCoO/硫化物固体电解质界面处的电容。实验结果表明，基于LiS-PS的固体电解质中具有快速传输速度的锂离子数量增加。同时，在WS和LiBr双掺杂后，基于LiS-PS的固体电解质与LiCoO阴极之间的界面电容降低，这表明掺杂的LiPS玻璃陶瓷电解质在离子电导率和界面相容性方面具有协同效应。这项工作可能为探索锂电池固体电解质的扩散动力学和界面行为提供一种新颖的分析方法。
