Prof. Cewen Nan
Materials Science and Engineering, Tsinghua University
Driven by solid-state lithium metal batteries with both high safety and high energy density, solid electrolyte materials have experienced a rapid development in the past years. Various solid electrolytes have been developed and the electrolyte/electrode interfaces are being extensively investigated. Some challenges remain for the applications of solid electrolytes in lithium metal batteries. In this talk, we are going to describe several kinds of solid electrolytes including oxide, sulfide, and composite electrolytes and discuss the challenges for high-performance solid-state lithium metal batteries. The preparation methods of various electrolytes are optimized and the relationship between the synthetic processes and the ionic conductivity of the electrolytes is studied. With the optimized electrolytes, solid-state lithium metal batteries are assembled and their cycle performance is systematically investigated. It is found that the interfaces between the solid electrolytes and the electrodes play an important role in the cell performance. On the anode side, a stable electrolyte/anode interface is critical for the long-term cycling of the lithium metal batteries. A surface treatment on the electrolytes such as LLZO can be carried out to significantly reduce the interfacial resistance and ensure a long life at high rates for the solid-state lithium metal batteries. As for the cathode side, it is also necessary to maintain an intimate interface during the cell cycling. With rational designs of solid electrolytes and proper interface engineering, high-performance solid-state lithium metal batteries are obtained.