Structural and ion transport properties of [(AgI)x(AgBr)0.4-x](LiPO3)0.6 and (AgBr)x(LiPO3)(1-x) solid electrolytes

The (AgBr)(x)(LiPO3)((1-x)) (x=0.4 and 0.5) and [(AgI)(x)(AgBr)(0.4-x)](LiPO3)(0.6) (x=0.1, 0.2, and 0.3) superionic electrolytes have been prepared by conventional melt quenching using a twin roller. These electrolytes are characterized by X-ray diffraction, SEM, and energy dispersive X-ray analysis (EDAX) for structural investigation. Electrical characterizations have been carried out by the AC impedance analysis. The conductivity of LiPO3 glassy system at room temperature is improved by doping with the silver bromide (AgBr)(x)(LiPO3)((1-x)) and the mixture of silver iodide, silver bromide (AgI-AgBr-LiPO3 system) up to 10(-5) and 10(-3-1)cm(-1), respectively (improvements by four or five orders of magnitude). The frequency response of ionic conductivity has been analyzed by universal dynamic response model (Jonscher's law) and AC conductivity data are fitted using the Jonscher's power law. The conductivity values obtained by the power law and impedance plots are comparable. The frequency exponent (n) has a value between 0 and 1. The AgI-AgBr-LiPO3 system shows the mixed alkali effect. Summerfield scaling master curve is temperature dependent, which may be due to the contribution of the both lithium and silver ions to ionic conduction.