Enhancing durability with Ni–GDC co-impregnated electrodes for solid oxide electrolysis cells

Solid oxide electrolysis cells (SOECs) are promising electrochemical devices for highly-efficient hydrogen production, but their long-term durability remains a critical challenge, particularly for SOEC electrodes operating under harsh highly-humidified electrolysis conditions. Conventional nickel–yttria-stabilized zirconia (Ni–YSZ) cermet cathode suffer from degradation associated with nickel aggregation and/or sublimation, limiting long-term stability. To address these challenges, we have developed Ni–GDC co-impregnated electrodes, in which metallic Ni and gadolinium-doped ceria (GDC) are impregnated onto a Ni-free stable backbone. This study focuses on the electrochemical performance and long-term durability of such electrodes for SOECs and related devices. 1000- h durability tests demonstrate that Ni–GDC co-impregnated electrodes exhibit significantly improved stability during steam electrolysis, corresponding to a tenfold reduction in the degradation rate of the cathode potential compared to Ni–GDC cermet electrodes. Notably, an electrode with a Ni:GDC volume ratio of 1:5 achieved the highest durability. These findings highlight that employing a Ni-free backbone decorated with highly dispersed Ni and GDC nanoparticles is an effective strategy for enhancing cathode durability of SOECs.