Electrical conductivity and oxygen relaxation behavior in BaBi 1- x Sr x Nb 5 O 15- δ tungsten bronze ceramics.

BaBiNb ₅ O ₁₅ (BBN) based oxide-ion conductors have great potential for application in intermediate-temperature solid oxide fuel cells. In this work, electrical property enhancement is achieved by Sr ²⁺ ion doping and sintering process improvement. The BaBi _{1- x} Sr _x Nb ₅ O _{15- δ} samples are prepared by the traditional solid-state reaction to investigate their electrical properties and oxygen relaxation behavior. Upon increasing the Sr ²⁺ doping amount, the bulk conductivity of BaBi _{1- x} Sr _x Nb ₅ O _{15- δ} compounds increases first and then gradually decreases, and the bulk conductivity of the sample is the best when the doping concentration is 2 mol%. With the increase of Sr ²⁺ doping, the activation energy shows a first decreasing and then increasing trend. Compared with the traditional sintering method, the total conductivity of the BaBi _0.98 Sr _0.02 Nb ₅ O _{15- δ} sample prepared by the two-step sintering method is greatly improved. These results have great implications for improving the electrical performances of BBN-based oxide conductors and studying their sintering process.