Stability and performance of tape cast anode supported electrolyte (ASE) cells

Recent progress in our development of anode supported electrolyte (ASE) SOFcells is reported. The cells are fabricated by cocasting of aqueous slurries of NiO/YSZ and 8YSZ, followed by cofiring. A gradient cathode is deposited by screenprinting successive layers of LSM/YSZ composite and lanthanum cobaltite, followed by a 2nd firing step. Full cells show a final thickness of ? 0.25 mm, high flexibility and reasonable warpage. Proper anode current collection is crucial and obtained by cofiring an additional outer layer together with the substrate. Power density can reach 0.2 W/cm2 at 600°C with active cathodes (LSC, short-lived) and >1 W/cm2 at 810°C with the LSM cathode. Stability was tested during 2900 h, giving an average degradation of 3%/1000 h at 0.5 A/cm2 current density. Degradation can be delayed by short-time polarisation at higher current density: e.g. “reactivation” at 0.85 A/cm2 (30 min.) delayed degradation by 300 h.