Research

Lithium-ion batteries are widely used as energy storage systems because of their high energy density. However, traditional lithium-ion batteries with liquid electrolytes have significant safety issues. The use of solid electrolyte instead of flammable liquid electrolyte can effectively solve the safety problem. Therefore, all-solid Li-ion battery has gradually become a focus of research in recent years. In addition, all-solid Li-ion battery also has the advantages of high energy density, long lifetime, and wide operating temperature range, which makes it promising to become the next generation of Li-ion battery.
However, there are still some key issues to be solved for all-solid-state lithium batteries. The low ionic conductivity of the solid-state electrolyte is an important factor limiting its performance, and the development of fast ionic conductors with high ionic conductivity can help achieve high charge and discharge rates of all-solid-state batteries. In addition, the electrode/electrolyte interface is also the focus of research. How to obtain stable interface with high ionic conductivity is major challenge for all-solid-state batteries. To address these key problems, our laboratory uses in situ transmission electron microscopy to observe the structural dynamic of solid-state electrolyte and electrode/solid state electrolyte interface at the atomic scale. We combine with other characterization tools to reveal the mechanism behind the phenomenon and provide guidance for the design of all-solid state lithium batteries with better performance.

Gas-phase in situ transmission electron microscopy is an important research method for exploring heterogeneous catalytic processes and has gradually developed into a frontier research method in recent years. Compared to traditional ex-situ structural characterization methods, gas-phase in-situ transmission electron microscopy allows the study of the structural evolution of catalysts under specific atmospheric and thermal field conditions at the microscopic scale. With DENSsolutions' unique gas-phase in-situ sample holder, combined with the new generation of transmission electron microscopy, our group can achieve TEM study under gas pressure up to 2 atmospheres and reaction conditions up to 1000 degrees, which helps to reveal near-realistic structural evolution information of heterogeneous catalysts under actual working conditions. This allows us to accurately establish the intrinsic correlation between structure and properties. To address the big data analysis challenges encountered in in situ structural characterization, the group has developed a series of artificial intelligence algorithms based on machine learning or deep learning, which help to mine the much-needed key physical and chemical information from in-situ diffraction, in-situ video and in-situ energy spectrum data. [Supported by Chinese National Natural Science Foundation and Strategic Priority Research Program (B)]