Optimization of electrocatalyst infiltration for enhanced performance in mixed ionic-electronic conductor-based solid oxide cells

The optimization of electrocatalyst infiltrate was carried out to enhance the performance of solid oxide fuel cells (SOFCs) with mixed ionic-electronic conductor (MIEC) Gd 0.1 Ce 0.9 O 2-δ (GDC) electrolytes. While infiltrated nano-catalysts based on Pr–Sr–Co (PSC) and cobalt-free Pr–Sr–Ni (PSN) and Pr–Sr–Fe (PSF) oxides exhibit high intrinsic catalytic activity, their morphological evolution with repeated infiltration cycles drastically alters full-cell electrochemistry. Inadequate loading limits phase connectivity, while excessive loading causes agglomeration and reduces the triple phase boundary. This study systematically investigates the impact of volumetric infiltrate loading on the microstructural connectivity, effective exchange current density ( i 0 ) , and area-specific resistance (ASR) of full cells utilizing a Pr and Sm-doped GDC scaffold. We demonstrate that in MIEC systems, the open-circuit voltage (OCV) and peak power density (PPD) are highly sensitive to catalyst loading. Comparison between before and after optimization revealed significant performance improvements. PSC and PSN exhibit impressive PPDs of 1.9 W/cm 2 and 1.7 W/cm 2 , respectively, at 650 °C, with remarkably low electrode polarization of 0.01 Ωcm 2 . Additionally, PSN demonstrated excellent long-term stability in full-cell tests, highlighting its potential as a robust cobalt-free electrode. This work demonstrates that optimized infiltration and catalyst selection are critical for maximizing cell performance.