Plasma Spray Coating on Interconnector Toward Promoted Solid Oxide Fuel Cells and Solid Oxide Electrolysis Cells
Newswise — Solid oxide cells (SOCs), including fuel cells (SOFCs) and electrolysis cells (SOECs), are highly efficient energy conversion devices. A key component in SOC stacks is the interconnector, which connects individual cells and separates gases. Metallic interconnectors, such as SUS430, are commonly used but suffer from high-temperature oxidation and chromium (Cr) poisoning, leading to performance degradation over time. Protective coatings can mitigate these issues, yet studies on their performance under thermal cycling conditions remain limited.
A study led by Professor Bo Yu from Tsinghua University, published in Frontiers in Energy, investigates the use of plasma-sprayed coatings to enhance interconnector durability. Researchers applied (La₀.₇₅Sr₀.₂₅)₀.₉₅MnO₃‑δ (LSM) and Mn₁.₅Co₁.₅O₄ (MCO) coatings via atmospheric plasma spraying (APS) and low-pressure plasma spray (LPPS). The study’s innovation lies in comparing these advanced spraying techniques under thermal cycling to evaluate coating stability and Cr migration inhibition.
MCO coatings, particularly those applied via LPPS, demonstrated superior performance. The MCO-LPPS coating exhibited the lowest initial area-specific resistance (ASR) of 0.0027 Ω·cm² at 800 ℃. After four thermal cycles, its ASR increased to 0.0032 Ω·cm², outperforming APS-applied coatings. Microstructural analysis revealed that MCO-LPPS formed denser, more uniform layers with lower porosity (3.4% vs. 5.6% for MCO-APS). Additionally, energy-dispersive spectroscopy confirmed that MCO-LPPS more effectively suppressed Cr diffusion at the coating-substrate interface after cycling.
This work provides critical data for designing durable SOC interconnectors, especially under frequent start-stop operations. The LPPS technique offers a viable route for producing high-performance MCO coatings that enhance oxidation resistance and limit Cr poisoning. Future studies will focus on validating these coatings in full SOC stacks under both SOFC and SOEC modes.
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Plasma Spray Coating on Interconnector Toward Promoted Solid Oxide Fuel Cells and Solid Oxide Electrolysis Cells, source
