High Ionic Conductivity in Composite Materials Under H2/Air Fuel Cell Condition

New ionic conducting electrolyte materials for solid oxide fuel cells (SOFCs), particularly intermediate temperature fuel cells have been attracting the interests of researchers in energy materials. The typical electrolytes used for SOFCs are normally single phase oxides. Here we report a series of conductive composites with high ionic conductivity derived from an electronic conductor such as a-LiFeO2 and an insulator such as g-LiAlO2. High conductivity was observed in the composites when prepared by a solid state reaction method. These composites also exhibit O2- or/and H+ ionic conduction which was confirmed through H2/air fuel cell measurements. An exceptionally high conductivity of 0.50 S/cm at 650 °C was observed under H2/air fuel cell condition. This provides a new approach to discover novel ionic conductors in composite materials.