Li15P4S16Cl3, a Lithium Chlorothiophosphate as a Solid-State Ionic Conductor

• Published in: Inorganic chemistry Vol. 59; no. 1
• Main Authors: Liu, Zhantao, Zinkevich, Tatiana, Indris, Sylvio, He, Xingfeng, Liu, Jue, Xu, Wenqian, Bai, Jianming, Xiong, Shan, Mo, Yifei, Chen, Hailong
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society (ACS) 12.12.2019
• Subjects: Crystal structure; Electrical conductivity; ENERGY STORAGE; Ions; Materials; Physical and chemical processes
• ISSN: 0020-1669; 1520-510X

Tremendous efforts have been devoted to the design of solid Li+ electrolytes and the development of all-solid-state batteries. Compared with conventional Li-ion batteries, which use flammable liquid organic electrolytes, all-solid-state batteries show significant advantages in safety. In this work, a novel lithium chlorothiophosphate compound, Li15P4S16Cl3, is discovered. The crystal structure and electrochemical properties are investigated. Li15P4S16Cl3 can be synthesized as a pure phase via a facile solid-state reaction by heating a ballmilled mixture of Li2S, P2S5, and LiCl at 360 degrees C. The crystal structure of Li15P4S16Cl3 was refined against neutron and synchrotron powder X-ray diffraction data, revealing that it crystallizes in the space group 1 (4) over bar 3d. The Li+ transport in Li15P4S16Cl3 was also investigated by multiple solid-state NMR methods, including variable-temperature NMR line-shape analysis, NMR relaxometry, and pulsed-field-gradient NMR. Li15P4S16Cl3 shows good thermodynamic stability and can be synthesized at relatively low temperature. Although it exhibits a low ionic conductivity at room temperature, it can serve as a new motif crystal structure for the design and development of new solid-state electrolytes.