3D Printing of Robust 8YSZ Electrolytes with a Hyperfine Structure for Solid Oxide Fuel Cells

Fully stabilized zirconia (8YSZ) has been considered a promising candidate for fabricating electrolytes of solid oxide fuel cells (SOFCs) due to the excellent oxygen ionic conductivity. Recently, structural optimization of a fully stabilized zirconia (8YSZ) electrolyte via vat photopolymerization (VP) technology has shown great potential in improving performance. Generally, preferable mechanical strength is required along with conductivity for the electrolyte structure. However, investigation on the mechanical properties of printed 8YSZ parts has been absent. Herein, an optimized 8YSZ photosensitive slurry was developed and the overall performance of the printed parts was tested systematically. The slurry with a high solid loading (50 vol %) exhibited a low viscosity (1.2 Pa·s, shear rate of 30 1/s). The printed parts showed superior mechanical (fracture toughness of 3.31 ± 0.38 MPa·m0.5, flexural strength of 372 ± 11 MPa) and electrochemical (ion conductivity of 4.03 × 10–2 S/cm at 800 °C) properties. Besides, the characteristic size of the prepared complex three-dimensional (3D) electrolyte structure was as small as 100 μm. Results indicated that the electrolytes achieved both comparable mechanical and electrochemical properties to those of conventional processes. Therefore, VP technologies open up an avenue for the fabrication of robust and geometrically hyperfine 8YSZ electrolytes with good electrochemical performance.