High performance, enhanced structural stability of co-sputtered nanocomposite anode with neutral stress state for low-temperature solid oxide fuel cells

Abstract

All-thin film solid oxide cells (ATF-SOCs) have exhibited exceptional performance at a wide range of operating conditions. However, despite the significant attention given to demonstrating the performance of ATF-SOCs, the correlation between their high performance and structural stability in comparison to sputtered metal or conventional sintered electrodes remains an area of active research. This study demonstrates high performance and enhanced thermal stability of co-sputtered nanocomposite Ni–Gd doped ceria (GDC) anode with extremely low contents of GDC. By tailoring the nanostructure of co-sputtered Ni-GDC anode with extremely low GDC contents, the electrochemical performance of TF-SOFCs increased more than 50% (749 mWcm–2 @ 500 °C) compared to the high-performance nanostructured Ni anode. This unconventional optimization of GDC composition ratio in co-sputtered Ni-GDC anode is attributed to the residual stress formed in thin film nanostructure. The analysis of residual stress has revealed that the increase in doped ceria contents in co-sputtered Ni-GDC increases the tensile stress in the thin film structure, causing the formation of cracks in the Ni-GDC anode with high ceria content in reducing environment. By controlling the GDC composition during the co-sputtering process, a neutral stress state was achieved in the co-sputtered nanocomposite, resulting in significantly enhanced performance and stability.