Organic Microemulsion Electrolytes for Advanced Metal Secondary Batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Current carbonate electrolytes limit high-performance lithium rechargeable batteries due to safety concerns, narrow operating temperatures, limited electrochemical windows, and chemical instability.
• Developing advanced electrolytes is crucial for next-generation batteries that operate under extreme conditions.

Purpose of the Study:

• To develop advanced organic microemulsion electrolytes (OMEs) that overcome the limitations of conventional carbonate electrolytes.
• To enhance the safety, stability, and performance of lithium rechargeable batteries, particularly at low temperatures.

Main Methods:

• Organic microemulsion electrolytes (OMEs) were synthesized by emulsifying high-molar-ratio electrolytes with nonpolar solvents and surfactants.
• The nonflammable LiFSI-TMP/TFEP/PFPN OME was characterized for its electrochemical properties and stability.
• Pouch cells utilizing the OME were assembled and tested for cycling stability, low-temperature performance, and safety (nail penetration test).

Main Results:

• The developed nonflammable OME exhibited intrinsic safety and high stability against graphite anodes and LiCoO2 cathodes.
• Pouch cells demonstrated long-term cycling stability over 200 cycles and excellent low-temperature performance.
• The OME successfully passed the nail penetration safety test, indicating enhanced safety.

Conclusions:

• The novel organic microemulsion electrolytes offer a promising alternative to conventional electrolytes for high-performance and safe lithium rechargeable batteries.
• The OME concept is extendable to other electrolyte systems, broadening the application of rechargeable batteries in extreme conditions.
• This work opens new avenues for electrolyte development by expanding solvent choices for advanced battery systems.