Thermal stability and decomposition of lithium bis(fluorosulfonyl)imide (LiFSI) salts
Journal article, 2016

The demand for lithium-ion battery (LIB) electrolytes with improved thermal stabilities, and maintained high ionic conductivities and electrochemical stabilities, has been the driving force behind the use of the lithium bis(fluorosulfonyl)imide (LiFSI) salt as a possible replacement for LiPF6. However, contradictory results have questioned its promising thermal stability and noncorrosive properties. Here the performance of three commercial LiFSI salts is compared with the focus on thermal stability and phase transitions together with a vibrational spectroscopy based assessment of the salt purity and decomposition products. The salts are found to differ significantly in their thermal stabilities as determined by both dynamic and isothermal TGA. In contrast, the FT-IR spectra of the salts are almost identical, while several additional bands are identified in the Raman spectra of the least stable salt. The latter allows for a discussion of the origin and role of salt impurities for the observed thermal (in-)stability. Overall the three salts show differences, but these differences are not straightforward to couple to any changes in the performance of Li/LiFePO4 cells using electrolytes based on these salts, but may nevertheless have implications on battery life-length and for application in various other battery technologies.

crystal-structure

behavior

carbonate solutions

electrochemical properties

liquid electrolyte

aluminum corrosion

perchlorate

transport

li-ion batteries

spectroscopy

Author

Manfred Kerner

Chalmers, Physics, Condensed Matter Physics

Nareerat Plylahan

Chalmers, Physics, Condensed Matter Physics

Johan Scheers

Chalmers, Physics, Condensed Matter Physics

Patrik Johansson

Chalmers, Physics, Condensed Matter Physics

RSC Advances

2046-2069 (ISSN)

Vol. 6 28 23327-23334

Areas of Advance

Transport

Energy

Materials Science

Subject Categories

Other Engineering and Technologies

Condensed Matter Physics

DOI

10.1039/c5ra25048j

More information

Created

10/8/2017