Planar Anode Supported SOFC Fabricated By Sequential Aqueous Tape Casting, Constrained Cosintering and Screen-Printing

Abstract

Hydrogen technologies and especially fuel cells, are promising alternatives to achieve a carbon-free energy and an ecofriendly transition [1]. The SOFC technology (Solid Oxide Fuel Cell) is an energy conversion system composed of a stack of a porous cathode, a dense electrolyte and a porous anode working at a temperature in the [600°C – 1000°C] range to obtain ionic conductivity above 10-2 S/cm. Nowadays, tape-casting is typically used for mass and low-cost manufacturing of supporting half-cell (8YSZ electrolyte and Ni-YSZ anode) and the cathode layer is commonly deposited by screen-printing [2]. In line with the cost reduction problematic, this presentation will describe the development and optimization of a green sequential tape casting process to obtain the anodic half-cell and screen-printing for the cathode. To target green process, aqueous based slurries are used and only non-toxic organic components are selected. The amount of organic components, ceramic powder and water was optimized to obtain slurries with a shear-thinning behavior while managing the powder dispersion stability. The parameters of the drying heat treatment have been optimized based on Thermal Gravimetric Analysis leading to obtain a multilayer flexible green tape without any bubbles or cracks further annealed to eliminate the organics and co-sinter the stack under a porous YSZ load. The flat anodic half-cell with a thin and dense layer of 8YSZ on a thick and porous layer of NiO-YSZ is completed by screen-printing of La2NiO4+ δ (cathode) based ink followed by a consolidation thermal treatment. The characterization using X-ray diffraction, scanning electron microscopy and operando electrochemical tests of the cell allow validating the efficiency of the sequential tape-casting to fabricate via environmentally friendly process and low cost SOFC. [1] Rissman, J. et al. (2020) ‘Technologies and policies to decarbonize global industry: Review and assessment of mitigation drivers through 2070’, Applied Energy, 266, p. 114848. doi:10.1016/j.apenergy.2020.114848. [2] Udomsilp, D. et al. (2021) ‘Performance Benchmark of Planar Solid Oxide Cells Based on Material Development and Design.’, Energy Technology, 9. doi:10.1002/ente.202001062.