BZCY (BaZr0.7Ce0.2Y0.1O3-δ) Powder as Proton-Conducting Electrolyte for Low Temperature SOFC/SOEC, 50 g/bottle, CLTSOFECPCEBZCY

In both Solid Oxide Fuel Cells (SOFC) and Solid Oxide Electrolysis Cells (SOEC), BZCY (Barium Zirconate Cerate Yttrate)—typically formulated as BaZr0.1Ce0.7Y0.2O(3-x), is the leading Proton-Conducting Electrolyte. While traditional SOFCs (like YSZ) rely on the movement of heavy oxygen ions (O^{2-}), BZCY allows for the transport of small, highly mobile Protons (H+). This fundamental shift in charge carrier enables efficient operation at significantly lower temperatures (400°C–600°C).

Using protons instead of oxygen ions provides three transformative benefits for fuel cell and electrolysis technology: (1) Lower Activation Energy: Protons are the smallest possible ions. Because of their size, they "hop" through the crystal lattice with much less resistance than large oxygen ions, allowing for high power densities at intermediate temperatures. (2) Fuel Side Product Generation (SOFC): In a proton-conducting SOFC (PC-SOFC), water is formed at the cathode (air side) rather than the anode. This prevents the fuel (hydrogen) from being diluted by water vapor, maintaining a high Nernst potential throughout the cell. (3) Direct Pressurized Hydrogen (SOEC): In electrolysis mode (SOEC), pure hydrogen is produced on the cathode side, while steam is fed to the anode. This simplifies the separation process and allows for the production of dry, high-purity hydrogen.

BZCY is a solid solution of Barium Cerate (BaCeO3) and Barium Zirconate (BaZrO3): (1) Barium Cerate (C): Provides exceptionally high proton conductivity but is chemically unstable; it reacts with CO2 to form BaCO3, causing the cell to crumble. (2) Barium Zirconate (Z): Is extremely stable against CO2 and moisture but has very poor conductivity due to high grain-boundary resistance. (3) Hybrid (BZCY): By combining them, BZCY achieves a "sweet spot"—it retains the high conductivity of the cerate while the zirconate fraction provides the chemical robustness needed to survive in real-world environments containing CO2.

References:

1. T. Kobayashi, et al., Analysis of the Anode Reaction of Solid Oxide Electrolyzer Cells with BaZr0.4Ce0.4Y0.2O3-δ Electrolytes and Sm0.5Sr0.5CoO3-δ Anodes, J. Electrochem. Soc., 2018, 165, F342.
2. H. Toriumi, et al., Enhanced Performance of Protonic Solid Oxide Steam Electrolysis Cell of Zr-Rich Side BaZr0.6Ce0.2Y0.2O3−δ Electrolyte with an Anode Functional Layer,  ACS Omega 2022, 7, 11, 9944–9950.