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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。
La0.7Sr0.15Ca0.15Co0.9Fe0.1O3-δ (simple: LSCCF) composite oxide was synthesized by coprecipitation method, citrate method and microwave solid-state sintering method. XRD and SEM were used to study the crystal structure and particle size of powders synthesized by different methods. The experimental results show that the LSCCF oxide with a single perovskite structure can be obtained by the three methods. Citric acid powder obtained by the smallest particle size, microwave sintering powder prepared the best dispersion. The conductivity of the LSCCF sintered samples from 100 ℃ to 800 ℃ was studied by using the DC quadrupole probe method under air atmosphere. The conductivity mechanism of the LSCCF samples was found to be in accordance with the p-type small polaron adiabatic pore theory. When the temperature is less than 655 ℃ , Its conductivity is mainly controlled by the exponential form and reaches the maximum value with the increase of temperature. When the temperature is higher than 655 ℃, its conductivity is determined by the pre-exponential factor and decreases with the increase of temperature. In the range of 600 ℃ -800 ℃ Of the conductivity of more than 500s · cm-1, to meet the medium temperature solid oxide fuel cell (ITSOFCs) cathode material requirements. The particle size, dispersibility and unit cell parameters of synthetic powders determined by different preparation methods determine the size of the conductivity. The order of influence is citrate method> microwave sintering method> coprecipitation method.