Liquid-phase sintering-driven Ni Cu alloy network enables exphed redox stability in GDC-based SOFC anodes

Solid oxide fuel cells (SOFCs) represent a highly efficient and clean energy conversion technology with promising application prospects. However, the metallic Ni in the Ni/GDC anodes of these devices undergoes significant volume expansion upon re-oxidation, leading to structural degradation. In this study, Ni-Cu/GDC anode-supported cells were fabricated by partially replacing NiO with CuO. The oxidative expansion behavior of both Ni-Cu/GDC and Ni/GDC anodes was analyzed at 700 °C. Furthermore, the electrochemical performance and redox stability of the SOFCs with these two types of anodes were compared. The results demonstrate that the introduction of Cu significantly enhances the deformation resistance of the anode under redox atmospheres. In electrochemical tests, the Cu10 cell endured more than 15 complete redox cycles without failure, whereas the Cu0 cell ruptured and failed after only 5 cycles. Furthermore, according to the Distribution of Relaxation Times (DRT) analysis, the increase in polarization resistance for the Cu10 cell following redox reactions can be attributed to the hindered adsorption and desorption processes of H 2 on the anode surface. This study proposes a plausible mechanism for the improved redox stability achieved through Ni Cu alloying. The enhanced redox stability of Cu10 is likely ascribed to the liquid-phase sintering induced by Cu addition, which accelerates the Ostwald ripening process. The resulting coarse and stable Ni Cu alloy particles mitigate the dimensional expansion of the anode, thereby reducing crack formation. • Cu incorporation markedly enhances the redox tolerance of Ni/GDC anodes. • Ni Cu alloying induces liquid-phase sintering and accelerates Ostwald ripening. • Cu10 anode shows 85% reduction in expansion strain and stable 15-cycle endurance. • EIS–DRT analysis reveals H₂ adsorption/desorption as the key degradation process.