Modified negative thermal expansion heterointerface engineering for thermally compatible La0.6Sr0.4Co0.2Fe0.8O3–δ-ZrW2O8 composite oxygen electrodes for solid oxide electrolysis cells

SOECs are promising for efficient green hydrogen production owing to high energy conversion efficiency and no requirement for precious-metal catalysts. However, interfacial stress associated with thermal-expansion mismatch remains a critical barrier to long-term durability. Herein, a modified negative thermal expansion (NTE) heterointerface engineering strategy is proposed by incorporating ZrW 2 O 8 (ZWO) into La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3– δ (LSCF) oxygen electrodes. During fabrication and operation, thermally driven reactions between LSCF and ZWO are associated with interfacial reconstruction, accompanied by the formation of SrWO 4 -related phases at the interface. This interfacial regulation mitigates thermal expansion mismatch and is associated with improved electrode durability and oxygen electrode polarization performance. The optimized LSCF-20ZWO oxygen electrode shows a 22.73% lower thermal expansion coefficient than pristine LSCF, delivering 2.61 A cm −2 at 1.4 V and 750°C with improved durability and thermal cycling tolerance. This work presents a feasible strategy for thermally compatible oxygen electrodes via modified NTE heterointerface engineering.