Solid oxide electrolysis cells (SOECs) are emerging as high-efficiency platforms for green H₂ and CO-rich syngas, enabled by high-temperature operation (600–900 °C), advanced oxygen-ion electrolytes (e.g., doped ceria, ScSZ, LSGM), and mixed ionic–electronic conductor (MIEC) electrodes. Recent single-cell advances deliver current densities from 0.5 to 5.73 A cm⁻² at the thermoneutral voltage (VTN; ≈1.286 V at 800 °C), with H₂ production rates up to 2.10 L h⁻¹ cm⁻² and near-100% Faradaic efficiency in steam electrolysis. Proton-conducting designs (e.g., BZCYYb) reach 1.0–2.3 A cm⁻² at 600 °C, indicating credible pathways to lower-temperature operation. Durability has improved markedly: representative planar fuel-electrode-supported stacks show 2 × manufacturing yield, >10,000 h stack life) for commercialization of SOEC-based hydrogen and e-fuels. • High-T SOECs achieve 0.5–5.73 A cm⁻² and near-100% Faradaic efficiency. • Durability rising: 23,000 h reliably. • System efficiency reaches 60–93% with strong heat-integration. • Co-electrolysis enables tunable H₂/CO for synthesis pathways. • Key gaps: electrode delamination, corrosion, and sealing resistance.
Lv et al. (2026) studied this question.