Why solid oxide cells can be reversibly operated in solid oxide electrolysis cell and fuel cell modes?

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• High-temperature solid oxide cells (SOCs) offer reversible operation for renewable energy storage and conversion.
• Performance stability, especially of oxygen electrodes in solid oxide electrolysis cell (SOEC) mode, is a critical challenge.
• La0.8Sr0.2MnO3 (LSM) is a common oxygen electrode material.

Purpose of the Study:

• To investigate the electrochemical activity and stability of LSM oxygen electrodes under cyclic solid oxide electrolysis cell (SOEC) and solid oxide fuel cell (SOFC) operation.
• To understand the degradation mechanisms and explore regeneration strategies for LSM electrodes.

Main Methods:

• Cyclic operation of SOCs in SOEC and SOFC modes.
• Electrochemical performance testing and analysis.
• In situ investigation of LSM/YSZ interfaces.

Main Results:

• Deterioration of LSM oxygen electrodes under anodic polarization (SOEC mode) can be partially or fully recovered by subsequent cathodic polarization (SOFC mode).
• The LSM/YSZ interface, crucial for cell performance, can be repaired and regenerated under cathodic polarization.
• Regeneration was demonstrated using in situ assembled LSM electrodes without pre-sintering.

Conclusions:

• The study demonstrates a method for regenerating degraded LSM oxygen electrodes, enhancing their stability in reversible SOC operation.
• This finding provides a foundation for developing durable and reversible SOCs for applications like hydrogen fuel production and electricity generation.
• Regeneration via cathodic polarization offers a pathway to improved long-term performance of SOCs.