One‐Pot Sol‐Gel‐Engineered Spray Drying of La _0.6 Sr _0.4 CoO _3–δ —Ce _0.8 Gd _0.2 O _2‐δ Electrode Composites for High‐Performance Solid Oxide Cells

ABSTRACT Achieving nanoscale homogeneity in biphasic air electrodes is critical for reversible solid oxide cells (RSOCs) but is often hindered by cation segregation in conventional synthesis. Here, a one‐pot Sol‐Gel Engineered Spray Granulation (SESG) strategy is designed to fabricate homogeneous La 0.6 Sr 0.4 CoO 3–δ ‐Ce 0.8 Gd 0.2 O 2‐δ (LSC‐GDC) composite electrode. By integrating chelation‐polymerization network into the spray‐drying process, SESG enables molecular‐level confinement of metal precursors and suppresses the formation of detrimental Ruddlesden‐Popper phases encountered in conventional spray drying. The resulting material exhibits high phase purity and an enhanced specific surface area of 12 m 2 ·g −1 . Consequently, the optimized SESG electrode delivers a peak power density of 0.50 W·cm − 2 in SOFC mode and a current density of 1.12 A·cm −2 (at 1.5 V) in co‐electrolysis mode, representing 25% and 15% enhancements, respectively, compared to electrodes prepared via conventional spray drying. The scalability of this approach is further validated in a 16 cm 2 large‐area cell, which achieves a high Faradaic efficiency (94.7%) and stable operation over a 100 h continuous test. Therefore, SESG represents a scalable, efficacious pathway toward high‐performance, durable air electrodes for practical RSOC applications.