Microstructure of Lithium Dendrites Revealed by Room-Temperature Electron Microscopy

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Lithium metal anodes are crucial for high-energy-density batteries but are limited by uncontrolled lithium dendrite growth.
• Investigating lithium dendrite microstructure is key to understanding and mitigating this issue.
• Current characterization methods like low-temperature transmission electron microscopy (LT-TEM) have limitations, with room-temperature characterization being underdeveloped.

Purpose of the Study:

• To develop and demonstrate room-temperature transmission electron microscopy (RT-TEM) for characterizing lithium dendrites.
• To compare RT-TEM with LT-TEM for analyzing lithium dendrite microstructure.
• To reveal the microstructural evolution of lithium dendrites during electrochemical cycling at room temperature.

Main Methods:

• Utilized transmission electron microscopy (TEM) with vacuum- and inert-gas-transfer methods for room-temperature analysis.
• Performed detailed comparisons between LT-TEM and RT-TEM characterization techniques.
• Employed RT-TEM for in-situ observations and 3D tomography of lithium dendrites.

Main Results:

• Successfully obtained the room-temperature microstructure of lithium dendrites.
• Demonstrated the advantages of RT-TEM, including flexibility for multifunctional characterizations like 3D tomography.
• Revealed microstructural evolution, including increased inorganic Li2O in the solid electrolyte interphase, lateral growth, and formation of inactive lithium during deposition/dissolution cycles.

Conclusions:

• Room-temperature TEM is a viable and advantageous method for studying lithium dendrites.
• RT-TEM provides insights into lithium dendrite evolution, including solid electrolyte interphase changes and inactive lithium formation.
• This work enhances the understanding of the structure-property relationship in lithium dendrites, crucial for advancing lithium metal anode technology.