Thiazolium Poly(ionic liquid)s: Synthesis and Application as Binder for Lithium-Ion Batteries

We report a synthetic route to thiazolium-type poly(ionic liquid)s (PILs), which can be applied as a polymeric binder in lithium-ion batteries. The ionic liquid monomers were first synthesized by quaternization reaction of 4-methyl-5-vinyl thiazole with methyl iodide, followed by anion exchange reactions to replace iodide by fluorinated anions to access a liquid state below 100 °C. Subsequently, these monomers bearing thiazolium cations in their structure underwent radical polymerizations in bulk to produce corresponding polymers. The dependence of solution and thermal properties of such monomeric and polymeric materials on the choice of the counteranion was investigated. Finally, the thiazolium-type PIL bearing a bis(trifluoromethanesulfonyl)imide (TFSI) anion was proven to be a high performance binder for lithium-ion battery electrodes.