Novel electrolytic systems composed from polymer polyethylene oxide are studied in the opening chapter of Liquid and Single Crystals: Properties, Manufacturing and Uses. Being of importance for electrochemical and other applications, the complex electrical impedance spectra and current-voltage characteristics of sodium ion-conductive PEO/E8LC/NaIO4 electrolyte films are analyzed and interrelated to their structural properties and thermal behaviors. Next, the authors discuss the recent development of various synthetic approaches and possibilities for chemical tuning of phosphates crystal...