Gas atomization spray pyrolysis derived hierarchically porous La0.6Sr0.4Co0.2Fe0.8O3–δ –Ce0.8Gd0.2O2–δ oxygen electrode toward high-efficiency solid oxide electrolysis cells

Solid oxide electrolysis cells (SOECs) represent a viable technology for green hydrogen production, capable of efficiently converting renewable electricity into storable chemical energy via steam electrolysis. However, intermediate-temperature SOECs (IT-SOECs) are severely constrained by sluggish oxygen evolution reaction (OER) kinetics at the oxygen electrode surface. The insufficient OER activity decreases the electrolysis efficiency of SOECs, remaining a key bottleneck for further practical applications. To address this issue, La0.6Sr0.4Co0.2Fe0.8O3–δ-Ce0.8Gd0.2O2–δ (LSCF-GDC) nanocomposites featuring interconnected multiscale pore structures and abundant heterophase interfaces were fabricated via a facile combination of gas atomization spray pyrolysis and mechanical ball milling. The optimized NiO-GDC|GDC|LSCF-GDC(7:3) single cell achieved a high electrolysis current density of 2.95 A cm−2 at 650°C under 1.3 V with 20 vol.% steam and exhibited long-term stability during a 350 hr continuous electrolysis test with a low degradation rate of 0.0152% per hr. This work proposes a feasible structural engineering strategy for SOEC oxygen electrodes, enabling efficient and durable hydrogen production at intermediate temperatures.