Limitation of thickness increment of lanthanum strontium cobaltite cathode fabricated by pulsed laser deposition

The limitation of thickness increment of a lanthanum strontium cobaltite cathode fabricated by pulsed laser deposition was investigated at a thickness range of 0.5-7 μm. The cell performance increased monotonically from 477 to 984 mW/ cm² at 0.7 V at 650°C [humidified H₂ (3% H₂ O) fuel and air] as the cathode thickens from 0.5 to 5 μm. This was attributed to the increase of the number of the electrode reaction sites along with the thickness of the cathode. However, the beneficial effect of further cathode thickness increment above 5 μm was limited by microstructural problems. Delamination at the electrolyte/cathode interface occurred in cells with cathode thickness of 7 μm, leading to an observed drastic drop in cell performance.