Development and Validation of Chromium Getters for Solid Oxide Fuel Cell Power Systems

Area of Science:

• Materials Science
• Electrochemistry
• Energy Conversion

Background:

• Solid oxide fuel cells (SOFCs) suffer long-term cathode degradation due to airborne chromium species, impacting performance and reliability.
• Chromium compounds form at the cathode-electrolyte interface, hindering the oxygen reduction reaction (ORR).

Purpose of the Study:

• To develop and validate a novel chromium getter technology to mitigate cathode degradation in SOFCs.
• To assess the effectiveness of low-cost getter materials in capturing gaseous chromium and preserving cell performance.

Main Methods:

• Synthesized low-cost getter materials from alkaline earth and transition metal oxides coated on cordierite honeycomb substrates.
• Screened getters using 500-hour chromium transpiration tests in humidified air with chromium vapor.
• Validated selected getters via electrochemical testing of LSM//YSZ//Pt SOFCs at 850 °C, with and without getters.

Main Results:

• Getters maintained stable SOFC electrochemical performance for 100 hours, while cells without getters degraded rapidly within 10 hours.
• Analysis of Nyquist plots showed a significant increase in polarization resistance within the first 10 hours for unprotected cells.
• Post-test characterization confirmed high chromium capture efficiency by the getters, mitigating cell degradation.

Conclusions:

• The developed chromium getters are highly effective in capturing gaseous chromium species, preventing cathode degradation in SOFCs.
• This getter technology offers a viable solution for enhancing the long-term stability and operational reliability of SOFC power systems.