| 摘要 |
There is disclosed new materials exhibiting high levels of mixed ionic and electronic conductivity at high temperatures (500-1000 DEG C) and low oxygen pressures (10<-13> - 10<-20> atm) suitable as a fuel cell anode. The material is based on the perovskite, strontium titanate, having a formula Sr1-xTiO3:n1%R1, where x is the fraction of vacancies and dopant atoms R1 on the strontium sublattice wherein 0.10 </= x </= 0.20, wherein 6-15 mol% of the strontium is replaced by R1 which is preferably yttrium or a late rare earth element from the group samarium, europium, gadolinium, terbium, disprosium, holmium, erbium, thulium, ytterbium and lutetium. Similar novel materials having the formula Sr1-xTi1-yO3:n1%R1,n2%R2 in which a fraction of the titanium is replaced by R2 which may be other transition metal ions or lower valent ions such as aluminium, gallium, also form part of the present invention. Electronic conductivities greater than 60 S/cm at 800 DEG C and at oxygen pressures of 10<-20> atm have been observed with the composition Sr.88Y.08TiO3- delta and more than 80 S/cm at the composition Sr.86Y.08TiO3- delta . |
