Fig. 5: Stefan–Maxwell analysis.

a Exponential decay of LiFSI thermodynamic diffusion coefficient (\({\mathfrak{D}}\)) with concentration. b Stefan–Maxwell coefficients \({{\mathfrak{D}}}_{0+}\), \({{\mathfrak{D}}}_{0-}\) and \({{\mathfrak{D}}}_{+-}\), all decreasing with concentration. \({{\mathfrak{D}}}_{0-}\) was generally the highest value across concentrations, indicating FSI⁻ had the least frictional interaction with G4, while FSI⁻’s frictional interaction Li⁺ was high. At 2 m, each Stefan–Maxwell coefficient was very similar, within error, which could illustrate a change in transport mechanism, from vehicular to ion-hopping. The error bars in (a) and (b) represent the standard error and propagation from previous calculations, see Supplementary Note 8.