Abstract
Nowadays, the ever-growing energy demands, the associated greenhouse gas emissions, and the exhaustible nature of fossil fuels are the biggest challenges of our industrial world. The use of clean and renewable energy is key to tackling the global warming impact and the associated worldwide climate crisis. Among various state-of-the-art technologies, fuel cells have shown great promise for the addressal of the above-mentioned issues because of their higher efficiency compared to conventional methods and significant potential for integration with worldwide net-zero carbon emission activities. Fuel cells can be divided into several classifications, such as PEMFC, PAFC, SAFC, AFC, MCFC, SOFC, etc., and are comprised of three main components: the anode, cathode, and electrolyte. The electrolyte layer, which is sandwiched between the anode and cathode layers, is known to be the heart of the fuel cell. Generally, fuel cells should have a good ion conductivity, high electrochemical performance, and a stable physical, chemical, dimensional, and morphological state in redox or oxidising environments. Solid oxide fuel cells (SOFCs) are of great importance among all fuel cells, due to their higher efficiency (80–85%) through the capture and reuse of waste heat. The electrolyte layer, which is sandwiched between the electrodes, is a solid material and should have a high density, high ionic conductivity (more than 0.1 S·cm−1), high thermal, physical, and chemical stability in redox environments, matching thermal expansion coefficient, etc. [1]. On the other hand, both electrodes should have an adequate porosity, high conductivity, and matching TEC, as well as thermal, chemical, and physical stability in different atmospheres. SOFCs can catalytically convert energy from fuels to electricity, and can be used in different designations, namely, in electrode-, electrolyte-, or metal-supported configurations. Each of these designations has some advantages over the other ones. In another classification, SOFCs can be divided into three different types according to their operating temperature: (a) high-temperature SOFCs (>800 °C), (b) intermediate-temperature SOFCs (600–800 °C), and (c) low-temperature SOFCs (<600 °C).