Stable Cu-Doped La₂NiO_4+δ Oxygen Electrodes for Solid Oxide Electrolysis Cells

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Engineering

Background:

• Solid oxide electrolysis cell (SOEC) technology offers efficient hydrogen production but requires performance and durability improvements.
• Strontium-containing oxides face challenges due to surface segregation and reactivity with impurities, hindering electrode activity and device longevity.
• Developing strontium-free oxygen electrodes is crucial for enhancing long-term SOEC operation.

Purpose of the Study:

• Investigate copper-doped La2NiO4+δ compositions with Ruddlesden-Popper structure for oxygen evolution reaction (OER) in SOECs.
• Evaluate the performance and stability of these novel strontium-free oxygen electrodes.
• Assess the scalability and applicability of the developed materials for practical SOEC devices.

Main Methods:

• Utilized small- and large-area planar electrode-supported SOECs for performance testing.
• Employed La2Ni0.8Cu0.2O4+δ (LNCuO-20) as the strontium-free oxygen electrode material.
• Conducted long-term stability tests at 750 °C in a 90% steam/hydrogen atmosphere versus air.

Main Results:

• La2Ni0.8Cu0.2O4+δ (LNCuO-20) achieved a current density of 1.2 A/cm² at 750 °C and 1.3 V.
• Demonstrated stable operation for over 1000 hours, indicating excellent durability.
• Validated material scalability and applicability using 13 cm² active area cells.

Conclusions:

• Copper-doped La2NiO4+δ presents a promising strontium-free alternative for SOEC oxygen electrodes.
• The developed material significantly improves SOEC performance and long-term stability.
• This advancement paves the way for more efficient and cost-competitive hydrogen production via SOEC technology.