Review of perovskite-structure related cathode materials for solid oxide fuel cells

In this article, different perovskite-structure related materials are reviewed, which could be potential candidates for cathode materials in solid oxide fuel cells. Solid oxide fuel cells provide an alternative, environmentally viable and efficient option to conventional electricity-producing devices. Different properties are required for the materials to qualify as a cathode for solid oxide fuel cells. Therefore, the analysis and review are done based on the process parameters and their effect on the electrical conductivity, electrochemical properties, the coefficient of thermal expansion and mechanical properties of different cathode materials. Fracture toughness and hardness have been the focus while analysing the mechanical properties. The selection of the initial composition, dopants and their valence plays a vital role in deciding the properties mentioned above of cathode materials. The prospective cathode materials classified as cobalt-based and cobalt-free are further bifurcated based on the A-site elements of the perovskite (ABO₃) structure. Also given in this article is the summary of the latest development on the cathode materials. As observed from the properties studied, cobalt-based materials tend to have higher conductivity than cobalt-free materials. While cobalt-free compositions are cost-effective and have a comparable coefficient of thermal expansion with other components of solid oxide fuel cells. The last section of the article gives the future scope of the research.