High power density thin film SOFCs with YSZ/GDC bilayer electrolyte

By Cho, Sungmee; Kim, YoungNam; Kim, Jung-Hyun; Manthiram, Arumugam & Wang, Haiyan
Published in Electrochimica Acta NULL 2011

Abstract

Bilayer electrolytes composed of a gadolinium-doped CeO2 (GDC) layer (∼6 μm thickness) and an yttria-stabilized ZrO2 (YSZ) layer with various thicknesses (∼330 nm, ∼440 nm, and ∼1 μm) were deposited by a pulsed laser deposition (PLD) technique for thin film solid oxide fuel cells (TFSOFCs). The bilayer electrolytes were prepared between a NiO–YSZ (60:40 wt.% with 7.5 wt.% carbon) anode and La0.5Sr0.5CoO3–Ce0.9Gd0.1O1.95 (50:50 wt.%) composite cathode for anode-supported single cells. Significantly enhanced maximum power density was achieved, i.e., a maximum power density of 188, 430, and 587 mW cm-2 was measured in a bilayer electrolyte single cell with ∼330 nm thin YSZ at 650, 700, and 750 °C, respectively. The cell with the bilayer electrolyte (YSZ ∼330 nm) doubles the overall power output at 750 °C compared to that achieved in the GDC single layer cell. This signifies that the YSZ thin film serves as a blocking layer for preventing electrical current leakage in the GDC layer and also provides chemical, mechanical, and structural integrity in the cell, which leads to the overall enhanced performance.

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