Towards the Microstructural Optimization of SOFC Electrodes Using Nano Particle Infiltration

Solid oxide fuel cells (SOFCs) are receiving increasing attention because of their ability to convert the chemical energy of fuels into electrical energy in an efficient and clean manner. It is generally accepted that electrode microstructure plays an important role in determining the performance and durability of SOFC electrodes because it has a significant influence on various transport phenomena and electrochemical reactions within the electrodes. In order to satisfy the growing demand for their performance and reliability, it is strongly required to understand the microstructure-performance relationships, and to optimize the microstructure.

Here we focus on electrodes fabricated with nano-particle infiltration technique, where ceramics structure constructs a framework structure called scaffold, to which nickel particles are introduced in the form of nano particles. 3D microstructural analysis using the focused ion beam scanning electron microscopy (FIB-SEM) (e.g. Figure) revealed that the infiltration technique has a greater potential, compared with the conventional powder mixing and sintering approach, to control the electrode microstructure, which is significantly useful to satisfy the requirements for the electrode microstructure, such as transport properties and electrochemical activities. Numerical simulations for the electrochemical and mechanical analyses are also conducted using the acquired 3D microstructures, delivering a guideline to optimize the electrode microstructure.

Figure. 3D reconstructed microstructure of an SOFC anode prepared using infiltration technique. A ceria scaffold (grey), infiltrated nickel particles (green) and extracted triple-phase boundary lines (red).