Comparative Analysis of Cobalt-Based and Cobalt-Free Infiltrated Nano-Catalyst Cathodes for Low-Temperature Solid Oxide Cells

Engineering nano-electrocatalyst infiltrated solid oxide cell cathodes could prove to be the key to overcoming lethargic oxygen reduction reaction at low temperature. Thermochemical reactions and particle agglomeration can result from high sintering temperature of traditional composite cathode, causing poor catalytic activity and low active surface area. This study demonstrates that, pure-phase electrocatalyst is not essential for achieving long-term stability or exceptional catalytic performance. This finding eliminates the need for high-temperature processing of catalytically active phase. Here we report multiphase nano-electrocatalyst cathodes prepared by solution infiltration method on Pr and Sm doped Gd0.1Ce0.9O2-δ mixed conducting scaffold. Through meticulous control of the formation temperature of the catalytically active phase and operating temperature, creating nanoparticles from a diverse range of materials was achievable. Multiphase Pr-Sr-Co (PSC) oxide-based and cobalt-free alternatives Pr-Sr-Ni (PSN) and Pr-Sr-Fe (PSF) oxide-based nano-catalysts were tested on symmetric cells, characterized, and analyzed. Cobalt-free PSN and PSF exhibited exceptionally low electrode polarization, with PSN achieving the lowest value (i.e., 0.06 Ω·cm² at 650°C) reported among cobalt-free materials. Moreover, PSN demonstrated an area-specific resistance comparable to its cobalt-based counterpart, PSC. This study presents a promising strategy to expand demand and reduce reliance on common materials for future solid oxide cell development.