探究低温共烧结制备具有Ni-GDC活性层的Ni-YSZ支撑固体氧化物电解池的可行性

Abstract Solid oxide cells (SOC) are attractive for large scale electrolysis because of their unmatched efficiency. The current performance limitation for fuel electrode supported cells, is the Ni-YSZ fuel electrode, which suffers critical degradation at high current density. This limits their hydrogen production capacity. Aiming to overcome said limitation, this work demonstrates the integration of Ni-GDC (Ce 0.9 Gd 0.1 O 1.95 ) fuel electrodes into co-sintered thin electrolyte cells. Ni-GDC is widely used in electrolyte supported cells without signs of similar degradation. The novelty of the manufacturing approach adopted was to reduce the co-sintering temperature to 1250 ∘ C to limit detrimental interdiffusion between GDC and the zirconia-based electrolyte. It was possible to make testable and gas-tight cells at 1250 ∘ C, and the temperature reduction was effective at reducing interdiffusion. However, microstructural characterization of the realized cells documented poor contact between GDC in the fuel electrode and the ScYSZ electrolyte (Sc 2 O 3 -Y 2 O 3 stabilized ZrO 2 ). This was the main cause for an approximate 50 pct drop in electrochemical performance compared to cells with Ni-YSZ electrodes. Despite the poor performance, the long-term stability was found to be improved relative to Ni-YSZ fuel electrode cells. One test operating between −1 and −1.75 A/cm 2 for more than 500 h showed no Ni migration. Moreover, it was found that this cell layout did not suffer mechanical failure despite large chemical expansions of GDC. If future work can solve the electrode-electrolyte contact issue, the reported cell concept has the potential to enable a significant increase in the area specific hydrogen production capacity of SOCs.