Assessing the Ion Transport Properties of Highly Concentrated Non‐Flammable Electrolytes in a Commercial Li‐Ion Battery Cell

Abstract

Abstract In order to assess the ion transport properties of alternative non‐flammable electrolytes in a typical commercial Li‐ion battery cell, we have measured the ionic conductivity and the lithium‐ion transference number under anion‐blocking conditions, , for two classes of highly concentrated battery electrolytes: (i) Mixtures of the ionic liquid N ‐methyl‐ N ‐propyl‐pyrrolidinium bis(fluorosulfonyl)imide (Pyr 13 FSI) with different amounts of the lithium bis(fluorosulfonyl)imide (LiFSI), and (ii) a solvate ionic liquid consisting of an equimolar mixture of tetraglyme (G4) and LiFSI. Together with previously published data on the solvate ionic liquid G4/LiTFSI (1 : 1), the obtained Li + ion transport data was used to estimate the overall resistance and the resulting maximum cycling rate of a commercial 10 Ah Li‐ion pouch cell containing these alternative electrolytes. Our results suggest that Pyr 13 FSI/LiFSI mixtures would allow for maximum charging/discharging rates close to 1 C, while the solvate ionic liquids would only support maximum rates of about 0.3 C.