Enhancing performance of lower-temperature solid oxide fuel cell cathodes through surface engineering

Solid oxide fuel cells (SOFCs) are recognized as highly efficient energy-conversion and ecofriendliness technologies. However, the high-temperature operation of conventional SOFCs at 800-1000 degrees C has hindered their practical applications due to the accelerated materials degradation and the resulting performance failures. Therefore, developing lower-temperature SOFCs (LT-SOFCs) seems necessary. With respect to LT-SOFCs, developing highly active cathode materials with long-term stability has been identified to be the priority, where cathode surface engineering has surfaced as a pivotal technique to bolster cathode functionality. This review delves into the myriads of surface modification strategies, including solution infiltration, atomic layer deposition (ALD), one-pot method, exsolution, pulsed laser deposition (PLD), and electrospinning (ES). Each method is scrutinized for its potential to enhance the cathode oxygen reduction reaction (ORR), a critical process in LT-SOFCs, while also fortifying the structural stability of cathode materials. This paper also meticulously evaluates recent breakthroughs in cathode surface engineering with highlighting the nuanced interplay between microstructural features and electrochemical performance. The technical challenges that persist in the practical application of LT-SOFCs are analyzed in this work and the possible further research directions are also suggested for overcoming the challenges towards significantly improved cathode performance including activity and stability.