This chapter reviews progress in infiltration technology and deals with the basic principle and typical process. It discusses the performance enhancement of infiltrated oxygen electrodes in solid oxide cells (SOC) and the unique advantages of infiltration technology, and highlights the future development of this technique. Despite numerous advantages and the broad application prospects, the large-scale application of SOCs devices is strongly limited by high operating temperatures. Extensive attention has been devoted to the enhancement of the performance and catalytic activity of SOC composite electrodes by using the method of infiltration, especially in solving the mismatch problems. Freeze casting can be used for preparing electrode/electrolyte supports in SOCs for more directional pores to release gas. The freeze casting method has the potential to synthesize specific morphology by controlling the freezing conditions. The chapter summarizes the fundamental solidification features of the freeze casting method, and critical factors such as dispersion media, additives, solid loading, and freezing conditions.