A structural study of solid electrolyte interface on negative electrode of lithium-Ion battery by electron microscopy

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Lithium-ion battery (LIB) performance improvements are ongoing, yet further enhancement is needed.
• Understanding electrode structure changes during cycling is crucial for LIB development.
• The solid electrolyte interface (SEI) on graphite anodes significantly impacts battery properties.

Purpose of the Study:

• To elucidate the SEI structure changes during the charge and discharge cycling of LIBs.
• To investigate the role of SEI formation and evolution in battery performance.
• To provide insights for controlling SEI to improve battery performance.

Main Methods:

• Utilized scanning electron microscopy (SEM) and transmission electron microscopy (TEM).
• Analyzed SEI structures on graphite anodes after specific charge/discharge cycles.
• Sampled electrodes at cutoff voltages of 3V and 4.2V (charge) and 3V (discharge).

Main Results:

• SEM images revealed clear changes in the SEI structure during cycling.
• TEM analysis showed the SEI layer thickness increases during charging.
• The SEI layer was observed to become thinner during the discharge process.

Conclusions:

• The study observed a reversible SEI structure change during LIB cycling.
• These findings offer new perspectives for advancing LIB technology.
• Controlling SEI structure is essential for future battery performance enhancements.