Enabling wide temperature battery operation with hybrid lithium electrolytes

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Developing electrolytes for lithium-ion batteries (LIBs) that operate across a wide temperature range is crucial for practical applications.
• Conventional electrolytes often suffer from poor performance or safety issues at sub-zero or elevated temperatures.

Purpose of the Study:

• To develop a hybrid electrolyte with an extended operational temperature window for LIBs.
• To evaluate the electrochemical performance of the hybrid electrolyte in a lithium titanate‖lithium cobalt oxide full-cell configuration.

Main Methods:

• Formulation of a hybrid electrolyte combining an ionic liquid (1-ethyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide) with propylene carbonate and lithium bis(trifluoromethanesulfonyl)imide.
• Fabrication and electrochemical testing of a lithium titanate‖lithium cobalt oxide full cell using the developed hybrid electrolyte.

Main Results:

• The hybrid electrolyte demonstrated a wide operational temperature window from -20 °C to 60 °C.
• The full cell exhibited high-rate capability at -20 °C, retaining over 40% capacity at a C/2 cycling rate.
• Negligible capacity fade was observed during rate capability tests and long-term cycling at 60 °C.

Conclusions:

• The developed hybrid electrolyte offers a promising solution for wide-temperature range LIB applications.
• The electrolyte's stability and performance at both low and high temperatures pave the way for more robust energy storage systems.