Performance of double-proveskite YBa_(0.5)Sr_(0.5)CO-2O_(5+δ) as cathode material for intermediate-temperature solid oxide fuel cells

摘要

Double-proveskite YBa_(0.5)Sr_(0.5)CO-2O_(5+δ) (YBSC) was investigated as potential cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs). YBSC material exhibited a good chemical compatibility with the La_(0.9)Sr_(0.1)Ga_(0.8)Mg_(0.115)Co_(0.085)O_(2.85) (LSGMC) electrolyte up to 950 ℃ for 2 h. The substitution of Sr for Ba significantly enhanced the electrical conductivity of the YBSC sample compared to undoped YBaCO_2O_(5+δ), and also slightly increased the thermal expansion coefficient. At 325 ℃ a semiconductor-metal transition was observed and the maximum electrical conductivity of YBSC was 668 S cm"1. The maximum power densities of the electrolyte-supported single cell with YBSC cathode achieved 650 and 468 mW cm~(-2) at 850 and 800 ℃, respectively. Preliminary results suggested that YBSC could be considered as a candidate cathode material for application in IT-SOFCs.