At present, the academic community has not fully studied the structural evolution of lithium sulfide during the operation of lithium-sulfur (Li-S) batteries. Whether the low electronic conductivity or low ionic conductivity of lithium inhibits the decomposition of lithium sulfide during charging is still controversial. In addition, the decomposition pathway of lithium sulfide is not clear.

Recently, the research team of Huang Jianyu, Tang Yongfu and Zhang Liqiang of Yanshan University addressed the above problems and combined PicoFemto®In-situ MST multi-field sample rod is used to study the precipitation and decomposition of lithium sulfide at high temperature. The results show that with the progress of lithiation at room temperature, lithium sulfide changes from amorphous/nanocrystalline to polycrystalline, and the precipitation of lithium sulfide at high temperature is more complete than that at room temperature. In addition, the study also found that the diffusion of lithium ions in solid-state lithium batteries is reversible. This work enables a new method to observe the lithiation behavior of lithium-sulfur batteries in situ at high temperatures. The relevant research results were published in Small under the title "In Situ TEM Observations of Discharging/Charging of Solid-State Lithium-Sulfur Batteries at High Temperatures. DOI: 10.1002/smll.202001899

Figure: Experimental Method

Experimental Platform Construction: The lithium-sulfur nano-battery consists of an S @ CNT nano-cathode and a lithium-plated metal anode. S @ CNTs are adhered to a flat aluminum rod at the tip, and lithium metal is coated on the other end. Aluminum rods are placed in the PicoFemto®The three-dimensional manipulation end of the in-situ MST multi-field sample rod accurately touches the heating zone on the MEMS heating chip through mechanical displacement, thus completing the construction of the entire nano-battery. In the experiment, the mechanical manipulation end, nano battery and MEMS chip form a closed loop to realize the in-situ charging and discharging of the battery. At the same time, the MEMS chip can also heat the battery at high temperature to study the charge and discharge behavior of the lithium-sulfur battery at high temperature.

Figure: In-situ TEM Observation Charge and Discharge

Figure: In-situ TEM Charge and Discharge Study at Different Temperatures Figure

Figure: theoretical model

Figure: In-situ sample rod used in the experiment