Suppressing Structure Delamination for Enhanced Electrochemical Performance of Solid Oxide Cells

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage and Conversion

Background:

• Reversible solid oxide cells (rSOCs) are promising for energy conversion and storage.
• Conventional air electrodes (LSM, BSCF, PBCC) suffer from interface delamination during operation.
• This delamination is linked to non-uniform cobalt valence states observed via micro-focusing X-ray absorption spectroscopy (µ-XAS).

Purpose of the Study:

• To develop a strategy to mitigate interface delamination in rSOC air electrodes.
• To improve the electrochemical performance and long-term stability of rSOCs.

Main Methods:

• Incorporation of oxygen-vacancy-enriched CeO2 into conventional air electrode materials (LSM, BSCF, PBCC) using a one-pot method.
• Analysis of electrode valence states using micro-focusing X-ray absorption spectroscopy (µ-XAS).
• Electrochemical performance testing, including long-term stability tests at 650 °C.

Main Results:

• CeO2 incorporation led to a uniform distribution of cobalt valence states, alleviating structural delamination.
• PBCC-CeO2 electrodes showed a significantly reduced degradation rate (0.095 mV h⁻¹) over ~500 hours compared to PBCC (0.907 mV h⁻¹ over 135 hours).
• Electrolysis current density and maximum power density increased substantially for PBCC-CeO2 compared to PBCC, with similar improvements observed for BSCF-CeO2 and LSM-CeO2.

Conclusions:

• The addition of CeO2 effectively stabilizes the electrode structure and mitigates delamination in rSOCs.
• This approach significantly enhances the electrochemical performance and operational durability of rSOCs.
• The findings provide a viable strategy for advancing the practical application of rSOC technology.