KAg4I5-AgI复合体系的电导率研究

摘要

KAg4I5（10%AgI） composite is prepared by the solid-state reaction method in the dark and dry conditions,and its structure,morphology,ion conductivity properties,and phase transition temperature are studied by X-ray diffraction,scanning electron microscope,impedance spectroscopy,differential scanning calorimetry and other analytical tools.The results show that when the two phases （AgI and KAg4I5 phases） in the composite are both fast ionic conductor phases,ionic conductivity of composite is higher than that of the single phase,and the heating and cooling of the conductivity curves form a hysteresis loop.During heating and cooling,AgI phase transition temperature lags 5 and 10℃ respectively.We use the interaction interface,the interface stress phase and Gouy-Chapman model to analyze the mechanism for the improved conductivity of this composite and phase transition temperature change when the two phases are both the fast ionic conductive.%采用固相反应法将市购的AgI和KI按4.1：1的摩尔组分配比,在避光干燥的条件下混合加热,制备出了KAg4I5（10%AgI）复合体系.用X射线衍射谱、扫描电子显微镜、复阻抗谱、差示扫描量热等分析手段,对复合体系的结构、形貌、离子导电特性及相变温度进行了研究.结果发现,两相均为快离子导体的材料复合后,其复合体系的离子电导率比各自为纯相时都高,并且升降温-电导率曲线为迟滞回线,AgI的升降温相变温度分别滞后5和10℃.用界面间相互作用、空间电荷模型及Gouy-Chapman模型、界面应力相等对此复合体系电导