Multidentate ether modifies solvation structure in nonflammable phosphate electrolytes for wide-temperature...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Conventional carbonate electrolytes for lithium-ion batteries (LIBs) exhibit limitations in wide-temperature performance and safety.
• Diethyl ethylphosphonate (DEEP) offers excellent flame retardancy and a broad operating temperature range, but faces challenges with graphite electrode compatibility and ionic transport.
• Addressing these limitations is crucial for developing advanced LIBs.

Purpose of the Study:

• To design a non-flammable, wide-temperature electrolyte for LIBs.
• To enhance the compatibility and ionic conductivity of DEEP-based electrolytes.
• To improve the overall performance and safety of LIBs.

Main Methods:

• Incorporation of diethylene glycol dimethyl ether (DEGDME) into DEEP-based electrolytes.
• Reconfiguration of electrolyte solvation structure to improve ion transport.
• Electrochemical testing of Li||Graphite and Graphite||LiFePO4 cells under various temperature conditions.

Main Results:

• The modified DEEP-based electrolyte demonstrated excellent film-forming properties, achieving 98% capacity retention after 150 cycles in Li||Graphite cells.
• Improved low-temperature performance was observed, with Graphite||LiFePO4 cells retaining 71% of their capacity after 50 cycles at -20 °C.
• The non-flammable electrolyte exhibited enhanced ionic transport and compatibility.

Conclusions:

• Diethylene glycol dimethyl ether (DEGDME) effectively reconfigures DEEP-based electrolytes for improved performance.
• The developed non-flammable phosphate electrolyte offers a promising strategy for safe, wide-temperature LIB applications.
• This research contributes to the advancement of safer and more reliable energy storage solutions.