Chemical synthesis of materials based on calcium zirconate for solid oxide fuel cells (SOFC)

Fuel cells allow the production of energy from a clean electrochemical reaction. Among various types, the solid oxide fuel cell (SOFC) operates at high temperatures, allowing the conversion of hydrogen fuel into electricity, where water is generated as a by-product. Strontium-doped lanthanum manganite (La1-xSrxMnO3, LSM) is commonly used as a cathodic material in traditional high-temperature solid oxide fuel cells. Nowadays, the operating temperature of SOFCs should be reduced to 600-800 degrees C due to improved fine electrolyte production techniques and the use of some intermediate temperature electrolytes. The LSM is not a suitable cathode for SOFCs operating in this temperature range, since it does not have a high enough conductivity and its electrochemical activity is very low as well. In this article, the performance improvement of LSM is described by mixing with calcium zirconate. The composite ceramic materials CaZrO3-La0.6Sr0.4MnO3, CaZrO3-NiO, and CaZrO3 were synthesized by combustion method, for application as a SOFC single cell. The results prove that the synthesized materials have potential to be used in a SOFC cell. At 800 degrees C, was confirmed the CaZrO3 formation. Through Electrochemical impedance spectroscopy, the analysis presented low activation energy and the materials have been demonstrated to be compatible, an important fact to construct a suitable SOFC cell. The obtained activation energy was 0.90, 0.85, and 0.51 eV for the electrolyte, the anode and the cathode, respectively.