Development of Coordination Space Controlled Materials and Their Application to Energy Devices

在这个项目中，我们的目标是开发协调空间控制材料，并将其应用于能源设备。我们专注于1）基于钙钛矿的新型质子导体的开发，2）新型混合（=离子和空穴（或电子））导体的开发，以及3）它们在能源设备中的应用，例如燃料电池。我们详细研究了LaScO_3基钙钛矿（Lal-xSrx）ScO_3-δ（x = 0.2，0.3）的导电性质，得到了"载流子图"。该图描绘了作为温度（T）、氧分压（P（O2））和氢分压（P（H2））的函数的主要电荷载流子（即，氧化物离子、质子、空穴和电子）域。结果表明，在600 ℃时，这些钙钛矿有望在燃料电池的阴极和阳极条件下作为质子导体工作。相对密度为98.2%的钙钛矿陶瓷可用于氢气传感器等。我们研究了质子导电钙钛矿中金属离子的电子态和局域结构（La1-xSrx）ScO 3-δ（x = 0.1，0.2，0.3）和混合（=质子和空穴）导电钙钛矿，具有LaScO3基本结构，（La0.8Sr0.2）（Scl-xMnx）O3-s（x = 0.1，0.25，0.5和0.75）（LSSM），通过粉末X射线衍射和La. L3-、Sc K-、Mn K-和Sr K-XAFS分析。质子传导钙钛矿的Sr K-和Sc K-XANES区域的比较揭示了预期与ScO6八面体配位的H+（或D+）离子的键合（即电子）状态可以根据Sr掺杂的量而表现出差异。LSSM的Mn K-XANES区域的比较表明，LSSM中的Mn离子将具有Mn 3 +/Mn 4+混合价。LSSM（x = 0.25 - 0.75）的总电导率测量结果表明，主要的载流子不是质子，而是空穴和（或）氧离子。

In this project we aim to develop coordination space controlled materials and apply them to energy devices. We focus on 1) development of perovskite-based new proton conductors, 2) development of new mixed (= ionic and hole (or electronic)) conductors, and 3) their application to energy devices, e.g. fuel cells. We have investigated in detail the conduction properties of LaScO3-based perovskites, (Lal-xSrx)ScO3-δ (x=0.2,0.3), and obtained the "Charge carrier map". The map depicts predominant charge carrier (i.e. oxide-ion, proton, hole, and electron) domains as functions of temperature (T), oxygen partial pressure (P(02)) and hydrogen partial pressure (P(H2)). It is found that at 600℃, those perovskites are expected to work as a proton conductor both under cathode and anode conditions of fuel cells. Also it was revealed that the thin ceramics of those perovskites with 98.2% relative density could be applied for H2 gas sensor and so on.We have studied the electronic states and local structures of metal ions in proton conducting perovskites (Lal-xSrx)ScO3-δ (x=0.1, 0.2, 0.3) and mixed (= proton and hole) conducting perovskites with LaScO3 basic structure, (La0.8Sr0.2) (Scl-xMnx)03-s (x = 0.1, 0.25, 0.5, and 0.75) (LSSM) by powder X-ray diffraction and La. L3-, Sc K-, Mn K-, and Sr K-XAFS analysis. The comparison of Sr K- and Sc K-XANES regions of the proton conducting perovskites revealed that the bonding (i.e. electronic) states of H+ (or D+) ions, which are expected to be coordinated to ScO6 octahedra, could exhibit difference depending on amount of Sr doped. The comparison of Mn K-XANES regions of the LSSM suggested that the Mn ions in the LSSM would have Mn3+/Mn4+ mixed valence. The results of total electrical conductivity measurements of LSSM (x=0.25-0.75) suggested the predominant charge carrier is not proton but hole and (or) oxide ion.