THERMALLY STIMULATED DISCHARGE CURRENT ANALYSIS OF POLYMERIC SOLID-STATE IONIC CONDUCTORS

Thermally Stimulated Discharge Current (TSDC) analysis was used to stu dy the electrical properties of two systems of polymeric solid-state i onic conductors. One system consisted of LiClO4 doped polyethylene gly col polyurethaneureas (PEUU) characterized by bi-ionic conduction and the other system was based on a sulfonated polyethylene oxide polyuret hane ionomer (SPUI) characterized by a single-ion transport mechanism. TSDC spectra of the PEUU as well as SPUI matrices showed four peaks ( gamma, beta, alpha, and rho). These peaks are found to be related to t he local motion of polyether soft segments, glass transition, Maxwell- Wagner-Sillars interfacial polarization and transport of charged ionic species, respectively. The discharge currents without polarization va rying with temperature for both, the PEUU-LiClO4 complex and SPUI, are also measured. These curves of discharge current show only one peak w hich is attributed to transport of charged ionic species. The temperat ure range in which the discharge current exhibits a steep increase is consistent with the temperature range in which a turning point appears on the plot of Ig sigma(i) versus 1000/T obtained by ac impedance ana lysis. The experimental results demonstrate that the TSDC analysis is a valuable tool for studying polymeric solid-state ionic conductors.