新型混合离子-电子导体Sm0.9Ca0.1Al1-xMnxO3-δ的制备及其电性能研究

采用有机凝胶法结合固相烧结技术制备了单相的Sm_0.9Ca_0.1Al_1-xMn_xO_3-δ（SCAM, x=0.1—0.5）新型混合离子-电子导体.通过TG-DTA，XRD和直流四引线法研究了凝胶前驱体的热分解和相转化过程、烧结体的结构、相稳定性、导电性能及其电输运机理.结果表明，凝胶前驱体在900℃焙烧5h可以形成完全晶化的四方钙钛矿相纳米粉体关键词：混合离子-电子导体3')" href="#">SmAlO₃有机凝胶法电导率

Preparation and electrical properties of the novel mixed ionic-electronic conductors Sm0.9Ca0.1Al1-xMnxO3

The novel mixed ionic-electronic conductors Sm_0.9Ca_0.1Al_1-xMn_xO₃ （SCAM, x= 0.1—0.5） were prepared by the organic gel method combined with solid state sintering technology. The thermal decomposition and phase inversion process of the gel precursors, crystal strucutres and phase stability of the sinters were studied by using thermogravimetric and differential thermal analysis （TG-DTA） and X-ray diffraction. The electrical conductivities of sintered ceramics in both air and 5%H₂/Ar were measured by the direct current four-wire method. The experimental results show that the well-crystallized nanopowders with tetragonal perovskite structure can be obtained after calcining the gel precursors at 900℃ for 5h, the phase stability of SCAM ceramics decreases with increasing Mn content under reduction atmosphere. The electrical conductivity of SCAM ceramics is dominated by p-type electronic conduction and increases with Mn content and temperature. The mechanism of electronic transport is the hopping of p-type small polaron. With increasing calcination temperature and prolonging holding time, both the electrical conductivity and relative density of SCAM9155 become large initially and then decrease. The SCAM9155 sample sintered at 1600℃ for 10h has the highest relative density of 98.2% and electrical conductivity reaching 7.30S/cm in air and 1.91S/cm in 5%H₂/Ar at 850℃. The apparent activation energies for SCAM9155 in air and in 5%H₂/Ar were calculated to be 0.273 and 0.371eV, respectively. The Ca- and Mn-substituted SmAlO₃ with relatively high conductivity may be used as a potential anode material for solid oxide full cells （SOFCs）.