Fluorinated Ester Electrolyte Additive

Enables -20°C Cycling

A small amount of ethyl pentafluoropropionate in carbonate electrolyte modifies the solvation structure to form a LiF-rich interphase, enabling stable cycling of LFP batteries at -20°C.

Xu, Caili · Zhang, Ming · Li, Pengyu · Chen, Cheng · Zhou, Haiping · Zhang, Shu · Wu, Mengqiang

Chinese Chemical Letters 2026

Specifications

Discharge capacity

{'zh': '117.2', 'en': '117.2'} mAh/g

Cycle number

{'zh': '130', 'en': '130'}

Additive amount

{'zh': '3', 'en': '3'} %

Cathode loading

{'zh': '8.5', 'en': '8.5'} mg/cm²

Advantages

Doubles low-temp capacity

At −20 °C, the cell with this additive delivers a specific capacity of 117.2 mAh/g, whereas conventional electrolytes suffer from significant capacity loss at this temperature.

Stable over 130 cycles

The cell exhibits stable cycling over 130 cycles at −20 °C, indicating that the LiF-rich interphase effectively suppresses side reactions and dendrite growth.

Only 3% needed

As little as 3% pFEP effectively modifies the solvation structure by increasing contact ion pairs and aggregates, promoting a uniform LiF-rich interphase that enables the low-temperature performance improvement.

Applications

• LFP batteries：The additive can be directly added to existing electrolytes, enabling LFP batteries to operate in cold environments without production line changes.
• low-temperature Li-ion：It addresses the severe capacity drop of Li-ion batteries below −20 °C, expanding their use in polar regions and winter outdoor applications.
• battery electrolytes：The additive tunes the solvation structure, offering a low-cost formulation for designing new low-temperature electrolytes.