IMPACT OF CALCINATION TEMPERATURE ON STRONTIUM CARBONATE FORMATION AND MICROSTRUCTURAL–THERMAL PROPERTIES OF SAMARIUM STRONTIUM COBALT OXIDE–SAMARIUM-DOPED CERIA CARBONATE COMPOSITE CATHODES FOR LOW-TEMPERATURE SOLID OXIDE FUEL CELLS

Siti Ameerah Nadiah Jamal; Sufizar Ahmad; Umira Asyikin  Yusop; Siti Fairus Mohammad; Hamimah Abd Rahman; Mohd Azham Azmi

Siti Ameerah Nadiah Jamal Faculty of Mechanical and Manufacturing, Universiti Tun Hussein Onn Malaysia, 86400 Parit Raja, Batu Pahat, Johor, Malaysia.
Sufizar Ahmad Faculty of Mechanical and Manufacturing, Universiti Tun Hussein Onn Malaysia, 86400 Parit Raja, Batu Pahat, Johor, Malaysia.
Umira Asyikin Yusop Solid Oxide Fuel Cell Group, Fuel Cell Institute, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia.
Siti Fairus Mohammad Faculty of Mechanical and Manufacturing, Universiti Tun Hussein Onn Malaysia, 86400 Parit Raja, Batu Pahat, Johor, Malaysia.
Hamimah Abd Rahman Faculty of Mechanical and Manufacturing, Universiti Tun Hussein Onn Malaysia, 86400 Parit Raja, Batu Pahat, Johor, Malaysia.
Mohd Azham Azmi Faculty of Mechanical and Manufacturing, Universiti Tun Hussein Onn Malaysia, 86400 Parit Raja, Batu Pahat, Johor, Malaysia.

Keywords: Ceria–based electrolyte, calcination, LT–SOFC, SSC–SDCC cathode, SrCO₃

Abstract

Solid oxide fuel cells (SOFCs) operating at low temperatures require cathodes with tailored microstructural and thermal properties to address performance challenges. The formation of SrCO₃ during the calcination process significantly influences the properties of the SSC–SDCC composite cathode for LT–SOFCs. This study systematically investigates the effect of calcination temperature (600 – 750 °C) on SrCO₃ formation and its correlation with the microstructural and thermal properties of SSC–SDCC (60:40 wt.%) composite cathodes. The cathode powders were mixed through the high–energy ball milling (HEBM) method and calcined at four different temperatures (600, 650, 700, and 750 °C). The pellet cathodes were fabricated using the uniaxial pressing method and sintered at 600 °C. Comprehensive characterizations using XRD revealed that calcination temperatures ≥700 °C effectively minimized SrCO₃ formation while maintaining phase purity. FESEM analysis revealed that all samples exhibited particle agglomeration, consistent with calcination powder theory, where particle bonding intensifies with increasing temperature. Porosity analysis reveals optimal cathode functionality with measured values of 35.91 – 38.78 %, residing within the established 20 – 40 % target range for effective gas diffusion while maintaining structural stability. The thermal expansion coefficients (15.1 – 16.00 × 10⁻⁶ K⁻¹) align well with ceria electrolytes (11.1 × 10⁻⁶ K⁻¹), exhibiting comparable thermal behavior while retaining beneficial SrCO₃ phases that enable functional compatibility. This systematic variation provides valuable insights for interface engineering in real–world SOFC operating conditions for the development of efficient and durable LT–SOFC systems for clean energy applications.