Novel lithium salt improves high-temperature resilience in Li-ion cells

Researchers at Huazhong University of Science and Technology in China are exploring the use of a novel lithium salt, lithium (fluorosulfonyl)(nonafluorobutanesulfonyl)imde (LiFNFSI), as conducting salt in the electrolyte to improve the high-temperature resilience of lithium-ion cells.

It shows better thermal stability than LiPF₆.

The electrolyte having 1.0 M LiFNFSI in a mixture of ethylene carbonate (EC)/ethyl methyl carbonate (EMC) (3:7, v/v) shows high conductivity comparable to LiClO₄, good electrochemical stability, and does not corrode aluminum. At both room temperature (25 °C) and elevated temperature (60 °C), the graphite/LiCoO₂ cells with LiFNFSI exhibit better cycling performances than those with LiPF₆.

Particularly, at 60 °C, the capacity fading rate of the LiFNFSI-based cell without any additive is 37% after 100 cycles, while the cell with LiPF₆ fails rapidly. These outstanding properties of LiFNFSI make it an attractive candidate to overcome the rapid capacity fading of lithium-ion batteries at elevated temperatures.

—Han et al.

Source: Green Car Congress