conductor Ba(Zr0.1Ce0.7Y0.2)O3-delta (BZCY7) as an electrolyte material for solid-oxide fuel cells (SOFCs) is investigated. The electrolyte material exhibits ionic conductivities (see figure) among the highest known for electrolytes viable for SOFC applications, and the chemical and thermal stability of BZCY7 appear adequate under a range of SOFC operating conditions. Several BZCY7-based single cells are fabricated using a modified dry-pressing method and show encouraging performance characteristics.