Poly(ethylene oxide) (PEO)-based electrolytes with Zn(II) salts systems have been re-examined and discrepancies found in the literature are discussed in terms of our own experimental results. Our electrolytes were prepared at room temperature, using acetonitrile as solvent for film-casting and the data were obtained with Films without any pre-heating. The electrolytes were characterized by X-ray diffraction, TGA/DTA, SEM and EIS, in the range of concentrations n=4-16. An intermediate compound with an n = 4 composition appears to exist in the PEOnZnCl2 system and a pseudo-equilibrium phase diagram has been drawn. Ongoing work for the PEOnZnI2 system, has provided evidence for the existence of an intermediate compound with the composition in the interval n = 4-8. A preliminary phase diagram is discussed.