Performance of Non‐Destructive Compressive Seals for Reversible Solid Oxide Cells

Abstract

AbstractContrary to hardened glass ceramics, compressive non‐destructive seals for solid oxide cells (SOCs) could enable stack repairs without utilizing destructive separation methods. In light of increasing interest for high temperature steam electrolysis and energy storage, the performances of two commercially available compressive materials were investigated in humidified gas conditions: Thermiculite‐866 and AFS‐170 alumina felts. Mass loss and thermogravimetric (TGA) experiments carried out in inert, oxidizing, and reducing atmospheres at 800 °C showed no influence of the atmosphere on the alumina felts, and a reversible redox behavior for Thermiculite‐866. Thermiculite‐866 showed better cyclability compared to AFS‐170 during SOC thermal cycling experiments. Initial open circuit voltages in dry H2 were measured and compared to those obtained with commercial mica seals. The highest were recorded with Thermiculite‐866, followed by mica and AFS‐170. The species outgassed by Thermiculite‐866 were quantified, and fluorine was found to be the main component released at 800 °C.