High-Efficiency CO₂ Electrolysis Enabled by Interface-Engineered Composite Electrolytes in Ni-Based SOEC

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Engineering

Background:

• Interfacial instability between yttria-stabilized zirconia (YSZ) and Gd-doped ceria (GDC) electrolytes causes delamination in solid oxide electrolysis cells (SOECs) during high-temperature operation.
• This thermal deformation disparity severely degrades SOEC performance and durability, hindering CO2 electrolysis commercialization.

Purpose of the Study:

• To resolve the interfacial instability issue in SOECs by designing a novel composite intermediate layer.
• To improve the structural stability, performance, and durability of SOECs for efficient CO2 electrolysis.

Main Methods:

• Fabrication of a composite intermediate layer using a simple dip-coating process with a mixture of YSZ and GDC powders.
• Integration of the composite interlayer into Ni-based fuel electrode-supported SOECs.
• Evaluation of interfacial stability, electrochemical performance, and long-term durability at high temperatures.

Main Results:

• The composite interlayer effectively mitigated thermal deformation disparity, ensuring excellent structural stability without delamination after high-temperature sintering.
• The cell with the composite interlayer exhibited significantly reduced interfacial resistance and achieved a high current density of 2.14 A cm⁻² at 800 °C.
• The SOEC demonstrated excellent long-term stability, retaining 91% of its initial performance after 80 hours of continuous operation under a harsh condition.

Conclusions:

• The engineered composite interlayer provides a robust solution to electrolyte interfacial instability in SOECs.
• This interface engineering strategy enables the development of high-performance and durable SOECs for CO2 electrolysis applications.