Fast ionic conducting film ceramic membranes with advanced applications

Fast ionic conducting film ceramic membrane materials have been successfully prepared via the soft-chemical synthesizing procedure, e.g. sol-gel and suspension processes. These film membranes are ionic and proton conducting Li₂SO₄-Al₂O₃, Li₂SO₄-SiO₂ composites, oxide ionic dominating conductors based on ceria-based oxides, and mixed conducting ceria-zirconia solid solutions. These thin film ceramic membranes are nanostructured with a thickness from 0.1 to several μm. Co-development of these conducting thin films as functional ceramic membranes is promising. One film can be thus used for a number of applications in advanced electrochemical or opto-ionic devices, e.g. fuel cells, electrochromic devices, and micro-batteries. A good example is CeO₂-ZrO₂ films which were used as the electrode material for the fuel cell, transparent counter electrode for the electrochromic or opto-ionic devices and Li⁺-intercalated electrode for secondary micro-batteries. This paper gives a brief overview of these new fast ionic conducting film ceramic membranes mainly in terms of their electrical properties and applications in the advanced ionic/electrochemical devices.