Nanoscale Ruddlesden–Popper infiltration of conventional LSM–YSZ oxygen electrodes: A barrier-layer-free route to durable solid oxide electrolysis

Conventional LSM–YSZ oxygen electrodes for solid oxide electrolysis cells (SOECs) suffer from sluggish oxygen evolution kinetics and progressive electrode–electrolyte degradation under sustained anodic polarization. We demonstrate that liquid-solution infiltration of Nd 2 NiO 4+ δ -dominant Nd–Ni–O nanoparticles into a conventional LSM–YSZ scaffold improves initial activity and lowers the operating voltage of full SOECs throughout extended operation, without an interfacial barrier layer. Under galvanostatic operation at −1 A cm −2 and 800 °C for ∼ 250 h, the NNO-infiltrated cell showed a lower initial voltage (1.08 vs. 1.30 V), no LSM activation transient, and a post-activation voltage drift reduced from 1.04 to 0.77 V kh −1 over a matched 48–240 h window, while operating 58–94 mV below the baseline throughout. Distribution of relaxation times analysis revealed elimination of the slow LSM surface exchange process, suppression of the high-frequency electrode–electrolyte degradation signature, and a shift from catastrophic interfacial failure to slower, kinetically-limited surface attrition. Polarization modeling gave an apparent exchange current density 1.30–1.65 × higher than the baseline at all matched timestamps, and post-test microscopy showed LSM–YSZ delamination and intergranular electrolyte separation in the baseline against an intact infiltrated interface. These convergent results establish nanoscale Ruddlesden–Popper infiltration as a scalable, barrier-layer-free strategy for SOEC oxygen electrodes.