Operando analysis of a solid oxide fuel cell by environmental transmission electron microscopy.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Conversion

Background:

• Correlating microstructure and performance in solid oxide fuel cells (SOFCs) is challenging due to complex material interactions and dynamic changes under operating conditions.
• SOFCs involve multiple material interfaces that degrade over time due to high temperatures and reactive environments.

Purpose of the Study:

• To demonstrate the utility of operando environmental transmission electron microscopy (E-TEM) for identifying structure-property relationships in SOFCs.
• To establish direct correlations between environmental conditions, microstructural evolution, and the performance of SOFCs at the atomic scale.

Main Methods:

• Utilized operando environmental transmission electron microscopy (E-TEM) in a single-chamber setup.
• Integrated a cathode-electrolyte-anode SOFC with a heating and biasing microelectromechanical system (MEMS).
• Controlled and varied environmental conditions (oxygen/hydrogen partial pressures, temperature) during E-TEM observation.

Main Results:

• Established a direct correlation between environmental conditions (pO2, pH2, T) and the open circuit voltage (OCV) of the SOFC.
• Observed and quantified microstructural evolution at the atomic scale under operando conditions.
• Linked the anode's oxidation state and morphology to the cell's electrical properties.

Conclusions:

• Operando E-TEM is a powerful tool for elucidating structure-property links in complex energy conversion devices like SOFCs.
• Understanding the dynamic microstructural changes, particularly in the anode, is crucial for optimizing SOFC performance and durability.
• The study provides critical insights into how anode oxidation state and morphology influence SOFC electrical characteristics.