Up-Scaling of Electrolyte-Supported Solid Oxide Electrolysis Cells for CO 2 Reduction

Abstract

CO2 electrolysis to CO by solid oxide electrolysis cells (SOECs) is a promising route for producing sustainable chemicals and fuels using renewable electricity. La0.8Sr0.2Ga0.8Mg0.2O3-x (LSGM)-based electrolyte-supported cells (ESCs) are an attractive configuration in SOEC because they enable flexible electrode choices, offering industrially relevant current density, energy efficiency, and long-term stability at high temperatures. While ESCs with a thin LGSM electrolyte layer demonstrates high efficiency at a small size (1 W), the fabrication, assembly, and testing of large cells are challenging: cracks may form due to sintering stress, and uneven pressure distribution during mounting can cause failure. Here, we address these challenges through a systematic engineering. A controlled stress-release sintering protocol prevents electrolyte cracking. A pressure distribution analysis and the subsequent addition of compressive buffer layers mitigate localized pressure and avoid structural failure. We obtain a 5 × 5 cm 2 LSGM-based ESC that achieves 1 A/cm² at 1.21 V and demonstrates 950-hour stability. Furthermore, we assemble a 5-cell stack that delivers a peak electrolysis power of 225 W, enabling a CO output of ~1.13 kg/day. This work establishes a scalable and mechanically reliable pathway for translating high-performance LSGM ESC concepts from single cells to stack-level operation under CO₂ electrolysis conditionsbstract text goes here.