Figure 3.

(A) A Robeson-inspired plot captures the traditional tradeoff between ionic selectivity (transference or transport number) versus permeability (conductivity). Unfilled symbols are values aggregated from a broad set of polymer electrolyte papers by Balsara and co-workers⁷ demonstrating the observed upper bound for these systems based on matrix molecular motion enabled ion transport. In comparison, the superionic PZILs studied here have comparable conductivities but much higher selectivities in comparison to the best conventional polymeric electrolytes. (B) The table indicates the selectivity metrics and conductivities for PZIL electrolytes. ρ₊ indicates the electrochemically determined limiting current fraction (Section 9 in the Supporting Information), and t₊ indicates the transport number determined by PFG-NMR (Section 7 in the Supporting Information). σ indicates the total ionic conductivity determined from EIS.