Chloride Ion‐Containing Polymeric Ionic Liquids for Application as Electrolytes in Solid‐State Batteries

Organic, solid-state batteries require efficient solid electrolytes able to provide stable ion conduction. Here, we present solid electrolytes based on ionic liquid (IL) polymers with chloride counterions as electrolyte materials for batteries. Acrylic monomers with imidazolium substituents with alkyl side groups that are linked by alkyl spacers to the acrylic group are employed. The IL monomers with chloride counterions are either converted by thermally initiated radical polymerization into linear homopolymers or incorporated into polymer networks by UV-initiated copolymerization utilizing a bifunctional, non-ionic crosslinker. Both procedures successfully yielded the desired materials, which was confirmed by NMR spectroscopy (linear homopolymers) or Raman spectroscopy (IL networks). The ionic conductivities at room temperature were measured by Electrochemical Impedance Spectroscopy. The ionic conductivities of the linear homopolymers are in the range of 10−4 to 10−6 S cm−1, while those of the IL networks were about two orders of magnitude lower. They increase to 10−4 S cm−1 at 70°C. The electrochemical stability was examined by Linear Sweep Voltammetry and is proven in the voltage range of -2 to +2 V. The results reveal that the materials represent promising electrolytes for potential solid-state battery applications. This article is protected by copyright. All rights reserved