Improving the degradation behaviour and coking resistance of solid oxide fuel cells via surface modification using wet impregnation of metallic solutions

Solid oxide fuel cells have reached a market-ready stage, with numerous industrial companies offering a diverse range of products. However, the significant challenge of fully leveraging the fuel flexibility of these devices remains unresolved. One promising approach is the introduction of small but meaningful modifications to commercially available materials, aimed at enhancing performance while minimising costs. In this context, surface engineering through wet impregnation of metallic solutions has demonstrated the potential for enabling complex modifications to electrode materials.

This study investigates the wet impregnation of Ce–Co–Mn and Ce–Co–La cation solutions onto the surfaces of commercially procured anodes, with the aim of improving power density, resistance to carbon deposition, and long-term operational stability. The solutions were prepared, applied, and sintered, followed by surface characterisation using X-ray diffraction and scanning electron microscopy. The cells were subsequently tested using hydrogen and simulated biogas as fuels, with the oxidant alternated between air and pure oxygen. After prolonged electrochemical testing under both potentiostatic and galvanostatic conditions, Raman spectroscopy was employed to evaluate potential carbon deposition.

Polarisation tests demonstrated the superior performance of the modified cells, achieving maximum power densities exceeding 435 mW cm⁻² with O₂ and 401 mW cm⁻² with air, compared to 301 mW cm⁻² and 401 mW cm⁻², respectively, for the benchmark. Additionally, sustained improvements in power densities were observed during extended static testing. Surface modifications were further shown to effectively inhibit carbon deposition, as verified through Raman spectroscopy. The transition between testing regimes offered valuable insights into the predominant degradation mechanisms under varying operational conditions.