Structure–Property Relationship of Polymerized Ionic Liquids for Solid-State Electrolyte Membranes

Eight new polymerized ammonium‐based ionic liquids were prepared as thin membrane
films and evaluated within the scope of their usage in lithium‐ion batteries. The focus of this work
is to get a better understanding of the influence of structural modifications of the monomers on the
polymerized materials. Further, different concentrations of a lithium‐ion conducting salt were applied
in order to receive an optimized combination of monomer structure and lithium salt concentration.
It was found that an increased side chain length of the studied ammonium‐based polymerized
ionic liquids leads to a reduction in glass transition temperatures and increased ionic conductivity
values. As a result of the addition of conducting salt to the PIL membranes, the glass transition
temperatures and the ionic conductivity values decreases. Nevertheless, PFG‐NMR reveals a higher
lithium‐ion mobility for a sample with higher conducting salt content.