Redox Stability Optimization in Anode-Supported Solid Oxide Fuel Cells

Area of Science:

• Materials Science
• Electrochemistry
• Mechanical Engineering

Background:

• Solid oxide fuel cells (SOFCs) utilizing Ni-YSZ anodes are prone to degradation due to volume changes during redox cycling.
• Oxidation of the Ni/NiO anode leads to expansion, inducing stress and potentially causing cell failure.

Purpose of the Study:

• To develop an analytical model to investigate the impact of anode architecture on the redox stability of Ni-YSZ SOFCs.
• To quantify the stress evolution in electrolyte and cathode layers under different anode configurations.

Main Methods:

• Development of an analytical model to simulate stress distribution within SOFCs.
• Parametric study on the influence of anode functional layer (AFL) and anode substrate thickness on stress.
• Comparative analysis of stress in SOFCs with and without AFL.

Main Results:

• SOFCs with an anode functional layer (AFL) exhibit increased tensile stresses (27.07% in electrolyte, 20.77% in cathode) after anode oxidation.
• Anode thickness significantly influences structural stability; increasing anode substrate thickness reduces electrolyte and cathode stresses.
• The anode substrate thickness is more critical for redox stability in SOFCs without an AFL.

Conclusions:

• Anode structure design is crucial for enhancing redox stability in Ni-YSZ SOFCs.
• Optimizing anode substrate thickness offers a viable strategy to mitigate stress-induced failure.
• The findings provide a theoretical framework for designing more robust SOFCs for redox-tolerant operation.