Conductivity studies on LiX-Li2S-Sb2S3-P2S5 (X=LiI or Li3PO4) glassy system

New sulfide glasses in the Li2S-Sb2S3-P2S5 system have been prepared by classical quenching technique where glassy domain remains up to 50% molar addition of Li2S and electrical conductivities have been determined by impedance spectroscopy. Room temperature DC conductivity vs Li2S content exhibits two regions implying different conductivity mechanisms. The compositions of low lithium content presented low electronic conductivities close to 0.01 mu S/cm at room temperature (due to Sb2S3 semiconducting properties). The compositions of medium lithium content could result to mixed ionic-electronic conductors with predominant ionic conductivity with a maximum close to 1 mu S/cm; Arrhenius behavior is found between 25 degrees C and T-g for all glasses, but activation energy is found to be somehow above most similar systems. A comparative study with glasses belonging to the other chalcogenide systems has been undertaken and values of the decoupling index are reported, and in order to validate conductivity data, a circuit equivalent circuit was proposed and fitted parameters were calculated with good agreement.