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In Situ Neutron Powder Diffraction Using Custom-made Lithium-ion Batteries
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Formation of LiF-rich Cathode-Electrolyte Interphase by Electrolyte Reduction
Panxing Bai1,2, Xiao Ji1, Jiaxun Zhang1
1Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD 20742, USA.
Angewandte Chemie (International Ed. in English)
|April 8, 2022
Summary
Researchers developed a robust LiF-rich cathode-electrolyte interphase (CEI) for high-voltage lithium-ion batteries. This new CEI significantly improves capacity retention and structural integrity in lithium cobalt oxide cathodes during extended cycling.
Area of Science:
- Materials Science
- Electrochemistry
- Energy Storage
Background:
- High voltage operation in transition metal oxide cathodes enhances Li-ion battery capacity.
- High voltage cathodes experience rapid capacity decay due to volume changes, cathode-electrolyte interphase (CEI) breakdown, and electrolyte penetration, leading to side reactions.
Purpose of the Study:
- To develop a stable cathode-electrolyte interphase (CEI) for high-voltage lithium-ion batteries.
- To improve the cycling stability and capacity retention of transition metal oxide cathodes.
Main Methods:
- Formation of a LiF-rich CEI via potentiostatic reduction of a fluorinated electrolyte at 1.7 V.
- Utilizing LiCoO2 as a model cathode to test the LiF-rich CEI at a high cut-off potential of 4.6 V.
Main Results:
- The LiF-rich CEI effectively maintained structural integrity and suppressed electrolyte penetration in LiCoO2 cathodes.
- LiCoO2 cathodes with the LiF-rich CEI achieved a capacity of 198 mAh/g at 0.5C.
- Enhanced capacity retention of 63.5% over 400 cycles was observed, compared to 17.4% for LiF-free cathodes.
Conclusions:
- A robust LiF-rich CEI can significantly enhance the performance and durability of high-voltage Li-ion battery cathodes.
- The developed CEI strategy offers a promising pathway for advancing high-energy-density Li-ion battery technology.
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