Recent advances, practical challenges, and perspectives of intermediate temperature solid oxide fuel cell cathodes

Abstract

As a highly efficient clean power generation technology, intermediate temperature (600–800 °C) solid oxide fuel cells (IT-SOFCs) have gained much interest due to their rapid start-up and shut-down capability, longer life-time and lower cost compared to the conventional SOFCs. However, the sluggish oxygen reduction reaction (ORR) at the cathode at lower temperatures, chromium (Cr) poisoning of cathodes when exposed to Cr-based interconnects, material degradation under CO₂ and humid atmospheres, and compatibility of Co-containing cathodes with existing IT-SOFC electrolytes still affect their large-scale development. This work aims to present an overview on the latest achievements in developing IT-SOFC cathodes based on perovskite-type and other crystal structures, and composites. The utilisation of distribution of relaxation times for analysing the impedance spectra of SOFC cathodes has been discussed. Furthermore, this article presents summary towards the rational design of the cathode materials and structures, to realize cost-effective and high-performance IT-SOFCs.