Abstract: The conductivity of the solid electrolyte based on urea and thiourea has reached 6.84 ×10^-3S.cm^-1 at room temperature. Analysing the conductive process of this electrolyte we found that thiourea changes into ammonium thiocyanate at a high temperature, which ionizes into ions, and can conduct the current. We obtained a red color substance through electrolysing the SPE. Analysing it with IR, UVand FAB, we confirmed that it is a polymer with a structure (SCN)_n. It is proved that the aninon is SCN^-. When weadded HCl into the acetone solution of the SPE, it was found that white precipitation material appeared in the solution, which was identified as NH₄Cl, so the canon is NH₄⁺.

Key words: Solid polymer electrolyte, Ionic conductivity, Anodic oxidational polymerization, FAB, IR, UV