In Situ Electrochemical Liquid Cell Electron Microscopy Study of Electrode-Electrolyte Interfaces

The electrode-electrolyte interfaces often play an important role in electrochemical devices, such as batteries or fuel cells. An understanding of the electrode-electrolyte interfacial phenomena can be significant for understanding the device failure mechanisms and improving the device performance. Our development of electrochemical liquid cell transmission electron microscopy (TEM) has enabled direct observation of many dynamic phenomena at electrode-electrolyte interfaces in nanometer resolution and in real time. With the in-situ electrochemical liquid cell TEM setup, we have been made achievements on the studies of lithium dendrite growth, solid electrolyte interphase (SEI), the electrode configuration on alkali metal deposition, etc.<br/>We have also studied lithium striping. As we know that an understanding of lithium stripping is as important as that of lithium plating to achieve significant advances in using lithium metal anodes for high-energy rechargeable batteries. However, there have been limited studies on lithium stripping compared to lithium plating. With in-situ electrochemical liquid cell TEM, we directly observed and compared the stripping behavior of the in-situ grown lithium dendrites and lithium nanograins on the electrodes. We found the sporadic lithium stripping behavior of lithium deposits regardless of their morphology. In addition, SEI chemical mapping with high spatial resolution showed a SEI loss at the end of the lithium metal stripping, illustrating the importance role of SEI in the subsequent cycles.