Asymmetric Imidazolium-Based Ionic Liquid Crystal with Enhanced Ionic Conductivity in Low-Temperature Smectic Phases

We report the synthesis and characterization of a novel asymmetric imidazolium-based ionic liquid crystal (ILC) dimer exhibiting stable smectic phases over a wide temperature range, including room temperature. This unique molecular structure, combining two distinct mesogenic cores, reduces packing density, which enhances ion mobility and achieves high ionic conductivity in the smectic phase (0.1 mS cm−1 at 40 °C). Electrochemical impedance spectroscopy (EIS) confirmed improved ionic conductivity at lower temperatures, along with a stable electrochemical window of ±3 V. Application as a solid-state electrolyte in an electrochromic device demonstrated effective switching behavior and reversible redox cycles. These findings suggest that this asymmetric imidazolium-based ILC is a viable candidate for advanced electrochemical applications due to its structural stability and anisotropic ionic pathways.