【摘要】 采用共沉淀法、柠檬酸盐法、微波固相烧结法合成了La0.7Sr0.15Ca0.15Co0.9Fe0.1O3-δ(简:LSCCF)复合氧化物。借助XRD和SEM对不同制备方法合成粉料的晶体结构和粒度形貌进行了研究。实验结果表明:三种方法均可制得单一钙钛矿结构的LSCCF氧化物。柠檬酸盐法制得粉料的粒度最小,微波烧结法制备的粉料的分散性最好。在空气气氛下使用直流四极探针法研究了LSCCF烧结样品从100℃到800℃时的电导率,发现该体系材料的导电机制符合p型小极化子绝热孔隙理论,当温度小于655℃,其电导率主要受指数形式控制且随温度增大而达到最大值;当温度大于655℃,其电导率由预指数因子决定且随着温度的升高而降低,在600℃-800℃范围的电导率都超过了500s·cm-1,满足中温固体氧化物燃料电池(ITSOFCs)阴极材料的要求。不同制备方法合成粉料的粒度、分散性和晶胞参数决定了电导率的大小,其影响次序为柠檬酸盐法>微波烧结法>共沉淀法。更多还原

【Abstract】 Compositely doped oxide La0.7Sr0.15Ca0.15Co0.9Fe0.1O3-δ(LSCCF) was synthesized using co-precipitation, citrate and microwave sintering methods. The crystal structure and the particle size micrograph of LSCCF powders synthesized by different methods were investigated with XRD and SEM. The experimental results show that the single perovskite phase of LSCCF can be synthesized by three methods. The particle size of LSCCF by sol-gel method was the smallest, the best separated property of LSCCF was obtained by microwave sintering method.The electrical conductivity of the sintered samples of LSCCF were measured by four-probe DC method from 100℃ to 800℃ in air. The conduction mechanism for LSCCF powders is attributable to the adiabatic-hopping of p-type small polarons. When the temperature is less than 655℃ the electrical conductivity of these materials is mainly controlled by the exponent and is progressively up to the maximum with the temperature ; When the temperature exceeds 655℃ the electrical conductivity of these materials is mainly controlled by the pre-exponent factor and decreases with the temperature.The electrical conductivity of LSCCF higher than 500 s·cm-1 from 600℃-800℃ can meet the demands for intermediate temperature solid oxide fuel cells (ITSOFCs).The order of the electrical conductivity was citrate method>microwave sintering method> co-precipitation method for their different particle size, separated property and unit cell parameter.更多还原