Imidazolium‐Based Poly(ionic liquid)/Ionic Liquid Ion‐Gels with High Ionic Conductivity Prepared from a Curable Poly(ionic liquid)

Ionic liquid (IL)‐based ion‐gel membranes were prepared from a curable poly(IL)‐based materials platform with the free ILs 1‐ethyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][TFSI]), bis(fluorosulfonyl)imide ([EMIM][FSI]), 1‐butylimidazolium bis(trifluoromethylsulfonyl)imide ([C 4 IMH][TFSI]), and ethylmethylammonium nitrate [EAN][NO 3 ] and evaluated for their ionic conductivity performance at ambient and elevated temperatures. The resulting cross‐linked, free‐standing ion‐gel membranes were found to have less than 1 wt% water (with the exception of [EAN][NO 3 ] which contained ≈20 wt% water). Increasing free IL content from 50 to 80 wt% produces materials with ionic conductivity values ≥10 –2 S cm −1 at 25 °C and ≈10 –1 S cm −1 at 110 °C. Additionally, ion‐gels containing 70 wt% of the protic ILs [C 4 IMH][TFSI] and [EMIM][FSI] display ionic conductivity values of ≈10 –3 to 10 −2 S cm −1 over the temperature range of 25–110 °C. image