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Updated: May 29, 2026
11:04
Synthesis of Ionic Liquid Based Electrolytes, Assembly of Li-ion Batteries, and Measurements of Performance at High Temperature
Published on: December 20, 2016
Tuning Reaction Pathways via Symmetric Fluorination Enables High-Temperature and High-Voltage Electrolytes
Fangyuan Cheng1,2,3, Wen Zhang1,2,3, Chun Fang4
1Eastern Institute for Advanced Study, Eastern Institute of Technology, Ningbo, China.
Angewandte Chemie (International Ed. in English)
|May 28, 2026
Summary
Molecular fluorination symmetry in electrolytes enhances the stability and safety of high-capacity nickel-rich cathodes. This strategy improves performance at high voltages and temperatures, crucial for advanced battery applications.
Area of Science:
- Materials Science
- Electrochemistry
- Energy Storage
Background:
- Nickel-rich layered oxide cathodes offer high energy density but face challenges with interfacial instability and thermal safety at high voltages and temperatures.
- Existing electrolyte formulations struggle to mitigate decomposition pathways, leading to capacity fade and safety concerns in demanding battery operations.
Purpose of the Study:
- To develop a novel electrolyte design strategy based on molecular fluorination symmetry to enhance the high-temperature performance and intrinsic safety of Ni-rich cathodes.
- To precisely control electrolyte decomposition pathways and suppress the formation of detrimental acidic byproducts.
Main Methods:
- Employed difluoro-symmetric substitution in electrolyte molecular engineering.
- Investigated synergistic fluorination to direct interfacial chemistry.
- Tested modified electrolytes in electrochemical cells under harsh conditions (4.5 V, 45°C).
Main Results:
- Modified cells retained 83% capacity after 300 cycles at 4.5 V and 45°C, with reduced gas generation and increased thermal runaway onset temperature.
- Large-format pouch cells (2 Ah) demonstrated excellent capacity retention (90% after 480 cycles at 45°C; 91% after 200 cycles at 60°C).
- The strategy effectively suppressed defluorination decomposition and acidic byproduct formation.
Conclusions:
- Molecular fluorination symmetry is a viable design principle for advanced electrolytes.
- This approach significantly enhances the high-temperature performance and safety of Ni-rich cathodes.
- The findings pave the way for more stable and reliable high-energy-density battery systems.
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