Synthesis and Characterization of 5-Cyanotetrazolide-Based Ionic Liquids.

New salts based on imidazolium, pyrrolidinium, phosphonium, guanidinium, and ammonium cations together with the 5-cyanotetrazolide anion [C₂N₅]⁻ are reported. Depending on the nature of cation-anion interactions, characterized by XRD, the ionic liquids (ILs) have a low viscosity and are liquid at room temperature or have higher melting temperatures. Thermogravimetric analysis, cyclic voltammetry, viscosimetry, and impedance spectroscopy display a thermal stability up to 230 °C, an electrochemical window of 4.5 V, a viscosity of 25 mPa s at 20 °C, and an ionic conductivity of 5.4 mS cm⁻¹ at 20 °C for the IL 1-butyl-1-methylpyrrolidinium 5-cyanotetrazolide [BMPyr][C₂N₅]. On the basis of these results, the synthesized compounds are promising electrolytes for lithium-ion batteries. [ABSTRACT FROM AUTHOR]