Synthesis strategies for BaCe0.7Zr0.1Y0.1Yb0.1O3-δ for the development of high-conducting solid oxide cell electrolyte

BCZY-Yb perovskites have recently garnered significant interest due to their high ionic conductivity and exceptional performance in low-temperature fuel cells. Particularly, mixed ion conductor BaCe0.7Zr0.1Y0.1Yb0.1O3-δ (BCZY-Yb) is known to exhibit rapid transport of both protons and oxide ions providing enhanced ionic conductivity at relatively low temperatures (400–600 °C) in comparison with other compositions. However, the synthesis of BCZY-Yb phase remains a significant challenge for the development of high density and higher conduction electrolytes. In this work, electrolytes produced by solid-state reactive sintering, low- and high-energy milling, and modified sol-gel synthesis methods are considered assessing the viability of producing suitable BCZY-Yb electrolyte and evaluating the impact of the production process on the microstructure and phase purity. The concurrent phase formation during solid-state reactive sintering and the use of low-energy ball milling lead to electrolytes with high porosity. Conversely, high-energy milling improves particle packing, though secondary phases at the grain boundaries persisted. The modified sol-gel synthesis confirms as one of the most promising methods for producing pure, high-density electrolytes with ionic conductivity exceeding 7 mS/cm at 600 °C.