Nanoscale and nano-structured electrodes of solid oxide fuel cells by infiltration: Advances and challenges

Solid oxide fuel cells (SOFCs) are the most efficient devices for the direct conversion of the chemical energy stored in fuels such as hydrogen and hydrocarbons into electricity. The development of highly efficient and robust SOFCs requires cathodes and anodes with high electrocatalytic activity for O2 reduction and direct oxidation of hydrocarbon fuels, respectively. Nanoscale engineering of electrode structures via metal salt solution impregnation or infiltration attracts increasing attention as the most effective way to develop highly active and advanced electrode structures for SOFCs. The infiltration method opens a new horizon in the advanced electrode development as the method expands the set of variable electrode materials combinations with the elimination of thermal expansion mismatch and the suppression of potential detrimental reactions between electrode and electrolyte materials. In this article, the advances and challenges in the development of nanoscale and nano-structured electrodes and the fundamental understanding of the remarkable enhancement in the electrode performance are reviewed and discussed with primary focus on the progress and status of the field in the last 5 years.

► Nano-structured electrodes of solid oxide fuel cells by infiltration is reviewed.
► Infiltration is the most effective method to develop advanced electrodes for SOFCs.
► Promotion effect of infiltrated nanoparticles can be structural and/or catalytical.
► Most significant challenge for nano-structured electrode is the long-term stability.