Low temperature solid oxide fuel cells with pulsed laser deposited bi-layer electrolyte

Abstract

Solid oxide fuel cells (SOFC) using a pulsed laser deposited bi-layer electrolyte have been successfully fabricated and have shown very good performance at low operating temperatures. The cell reaches power densities of 0.5 W cm −2 at 550 °C and 0.9 W cm −2 at 600 °C, with open circuit voltage (OCV) values larger than 1.04 V. The bi-layer electrolyte contains a 6–7 μm thick samarium-doped ceria (SDC) layer deposited over a ∼1 μm thick scandium-stabilized zirconia (ScSZ) layer. The electrical leaking between the anode and cathode through the SDC electrolyte, which due to the reduction of Ce 4+ to Ce 3+ in reducing environment when using a single layer SDC electrolyte, has been eliminated by adopting the bi-layer electrolyte concept. Both ScSZ and SDC layers in the bi-layer electrolyte prepared by the pulsed laser deposition (PLD) technique are the highly conductive cubic phases. Poor conductive (Zr, Ce)O 2-based solid solutions or β-phase ScSZ were not found in the bi-layer electrolyte prepared by the PLD due to low processing temperatures of the technique. Excellent reliability and flexibility of the PLD technique makes it a very promising technique for the fabrication of thin electrolyte layer for SOFCs operating at reduced temperatures.