Mapping Out Fast Charging Safe Limits for High-Loading Lithium-Ion Cells by High-Fidelity Operando Microscopy

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-ion batteries (LIBs) dominate energy storage but face challenges in cycle life and safety due to lithium plating during fast charging.
• Lithium plating causes irreversible capacity loss and can lead to thermal runaway, posing significant safety risks.

Purpose of the Study:

• To develop a direct and accurate method for detecting the onset of lithium plating in realistic battery configurations.
• To improve the safety and performance of lithium-ion batteries by enabling faster charging without compromising cycle life.

Main Methods:

• Fabrication of transparent micro-LIBs in glass capillaries to mimic practical cell geometry.
• Utilizing operando microscopy for direct, non-damaging observation of lithium plating.
• Testing with an ether-based electrolyte and validating findings in coin cells with commercial materials.

Main Results:

• Direct observation of minute lithium plating, overcoming limitations of traditional electron or X-ray techniques.
• Demonstrated up to a 54% improvement in charging capacity before lithium plating onset using an ether-based electrolyte.
• Successfully replicated improved charging capacity in coin cells, confirming practical applicability.

Conclusions:

• Transparent micro-LIBs offer a viable platform for studying lithium plating dynamics.
• The findings enable the development of battery management systems for safe fast charging by providing a performance map based on temperature and charging rate.
• This research contributes to enhancing the cycle life and safety of lithium-ion batteries.