Abstract: A novel cerium substituted perovskite material is disclosed which may be used as an electrode, current collector or membrane in an electrochemical device such as a solid oxide fuel cell (SOFC) or an oxygen generator. The novel material may be provided as a composite material if desired. It has been found that examples of this material and its composites exhibit greatly improved electrochemical and electronic performance when used as a cathode material, current collector, membrane or the like in an electrochemical device such as a fuel cell or oxygen generator for example.