Yi Huaibo, Lv Yun, Wang Yanhui, Fang Xue, Mattick Victoria, Xu Jungu
MOE Key Laboratory of New Processing Technology for Nonferrous Metals and Materials, Guangxi Universities Key Laboratory of Non-ferrous Metal Oxide Electronic Functional Materials and Devices, College of Materials Science and Engineering, Guilin University of Technology Guilin 541004 P. R. China
Department of Chemical Engineering, University of South Carolina Columbia SC 29201 USA.
RSC Adv. 2019 Jan 30;9(7):3809-3815. doi: 10.1039/c8ra08254e. eCollection 2019 Jan 25.
Although mayenite CaAlO has been known as an oxygen ion conductor for several decades, its relatively low oxide ion conductivity limits its applications in electrochemical devices. Thus, many efforts have been made by researchers, employing a doping strategy, in order to further improve its ionic conductivity, but with little success. In this work, a series of pure phase CaAl Ga O (0 ≤ ≤ 1.2) materials were synthesized by a traditional solid state reaction method. Scanning electron microscopy (SEM) combined with energy dispersion spectrum (EDS) analyses disclosed well-sintered ceramics with uniform Ga distributions. The defect formation energies for Ga replacing the two distinguishable Al1 and Al2 sites in CaAlO calculated by static lattice atomistic simulation are nearly identical, ∼3.03 and ∼3.04 eV, respectively, consistent with the results of Rietveld refinements based on the XRD data, from which no preferred distribution of Ga on Al1 or Al2 site was observed. The electrical properties investigated by alternating current (AC) impedance spectroscopy show increased bulk conductivities for 0 ≤ ≤ 0.4. Thus, here we present the first work that successfully improves the bulk oxide ion conductivity of CaAlO by Ga-doping.
尽管钙铝石CaAlO作为一种氧离子导体已为人所知数十年，但其相对较低的氧化物离子电导率限制了其在电化学器件中的应用。因此，研究人员进行了许多努力，采用掺杂策略来进一步提高其离子电导率，但收效甚微。在这项工作中，通过传统的固态反应方法合成了一系列纯相CaAlGaO（0≤≤1.2）材料。扫描电子显微镜（SEM）结合能谱（EDS）分析表明陶瓷烧结良好，Ga分布均匀。通过静态晶格原子模拟计算得出，Ga取代CaAlO中两个可区分的Al1和Al2位点的缺陷形成能几乎相同，分别约为3.03和3.04 eV，这与基于XRD数据的Rietveld精修结果一致，从中未观察到Ga在Al1或Al2位点上的优先分布。通过交流（AC）阻抗谱研究的电学性质表明，对于0≤≤0.4，体电导率有所增加。因此，我们在此展示了第一项通过Ga掺杂成功提高CaAlO体氧化物离子电导率的工作。
