Innovative Approach on Nano-Structuring of Electrode for Solid Oxide Cells

Abstract

Solid oxide cells (SOCs) are electrochemical systems capable of operating reversibly and therefore may serve as versatile energy converters. Electrolysis mode, electricity can be converted to fuels or other valuable chemicals, on the other hand, fuel cell mode converts efficiently fuel to electricity on demand. Due to their severe operating conditions, the ideal fuel electrode materials has not been found yet to accomplish of its requirements such as electronic and ionic conductivity, and catalytic activity with strong stability in redox condition, while several high performance air electrode materials -have been identified. For a long time, Ni-YSZ cermet has been regarded as the embodiment of this functional trinity. However, even though degradation associated with reversible operation can be mitigated, the cermet electrodes still suffered from agglomeration during redox condition. Recent electrode designs have been developed to microstructures consisting of a porous mixed ionic electronic conductor backbone decorated with metallic nanoparticles (typically Ni) by impregnation method. However, these are still hindered by the lack of cost and time-effective methods to produce both robustness and high-performance from their nanostructured electrodes. Here, a simpler alternative, will be introduced, exsolution whereby the catalytically active metal is substituted in the crystal lattice of the backbone in oxidizing conditions and exsolved on the surface as designed metal particles under reduction condition. Here we demonstrated a simple and highly effective in situ method for producing nanostructured electrodes capable of delivering high performances in both fuel cell and electrolysis mode. Both the nanostructures and corresponding electrochemical activity show no degradation over 150 hours of testing.