Characterising Lithium-Ion Electrolytes via Operando Raman Microspectroscopy

11 December 2020, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


Knowledge of electrolyte transport and thermodynamic properties in Li-ion and ”beyond Li-ion” technologies is vital for their continued development and success. Here, we present a method for fully characterising electrolyte systems. By measuring the electrolyte concentration gradient over time via operando Raman microspectroscopy, in tandem with potentiostatic electrochemical impedance spectroscopy, the Fickian ”apparent” diffusion coefficient, transference number, thermodynamic factor, ionic conductivity and resistance of charge-transfer were quantified within a single experimental setup. Using lithium bis(fluorosulfonyl)imide (LiFSI) in tetraglyme (G4) as a model system, our study provides a visualisation of the electrolyte concentration gradient; a method for determining key electrolyte properties, and a necessary technique for correlating intermolecular electrolyte structure with the described transport and thermodynamic properties.


electrolyte concentration gradient
Raman microspectroscopy
lithium electrolyte
lithium ion batteries

Supplementary materials

Characterising lithium-ion electrolytes via operando Raman microspectroscopy Supporting Information


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