Abstract:

Gd₂O₃-doped CeO₂ (GDC) barrier layer is an important component of solid oxide fuel cell (SOFC), which can effectively prevent the side reaction between the high-performance cathode La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ (LSCF) and Y_0.16Zr_0.84O_2-δ (YSZ) electrolyte. However, the GDC barrier layer prepared by traditional wet ceramic technology has low densities and large thicknesses, which not only cannot effectively prevent the diffusion of Sr and other elements, but also increases the ohmic impedance of the cell; while the advanced coating technology can prepare ultrathin dense GDC isolation layer, but its industrial cost is high, and its application is difficult to be popularized and adapted poorly for the surface of non-flat-plate-type cell. In the previous research work, a new method of preparing dense GDC barrier layer was proposed, and an ultra-thin and dense GDC barrier layer was successfully grown on the surface of the YSZ electrolyte of the anode support by hydrothermal in-situ growth, and the produced single cell also had excellent electrochemical performance. On the basis, the hydrothermal in-situ growth technique was adopted to scale up the solution volume by 60 times. A continuous dense GDC barrier layer of 0.7 μm thickness was successfully prepared on the surface of YSZ electrolyte of 10 cm x 10 cm industrial-sized anode-supported single-cell by hydrothermal in-situ growth. The GDC/YSZ bilayer electrolyte was constructed, significantly reducing the cell's interfacial resistance and improving its output performance. The output power of the single cell reached 61.6 W at 720 ^oC under the working condition of 0.7 V. The present work realizes the low-cost preparation of dense GDC barrier layer for industrial-sized SOFC single cells and the high-performance output of SOFC single cells, and verifies the feasibility of the hydrothermal in-situ growth technology for industrial applications.

Key words: industrial-sized SOFC, GDC barrier layer, hydrothermal in-situ growth, electrolytes, interface