Characterization and optimization of new fluorite-related oxide ion conductors

新型萤石相关氧化物离子导体的表征和优化

• 批准号: EP/D077745/1
• 负责人: Saiful Islam
• 金额: $ 13.56万
• 依托单位: University of Bath
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2006
• 资助国家: 英国
• 起止时间: 2006 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FD077745%2F1
• 关键词: Characterization; optimization; new; fluorite; related

It is commonly assumed that solids which conduct electricity do so via the movement of charged electrons under an applied electric field, and electrically conducting liquids require the movement of charged ions. However, this is not always the case. Liquid mercury provides, perhaps, the best example of a liquid showing metallic (electronic) conduction, and there are a variety of solids whose conductivity is primarily due to ionic migration. Such solids may therefore show similar properties, and applications, as liquid electrolytes. An important application for solids which conduct via the migration of O2- ions is as electrolytes for high temperatures solid oxide fuel cells, SOFCs, where the electrolyte separates the active electrode materials, which may simply be O2 and H2. Other applications include O2- conducting membranes which can, for example, be utilised for the production of pure oxygen from impure sources, typically air, by passing a current through the membrane. Such devices could be used for large scale oxygen production or in portable devices, e.g. for medical purposes. For efficiency and technological stability, low temperature operation is a requirement, and the need for new materials which show high O2- conductivity at low temperatures provides the stimulus for this proposal. We have made an important observation that certain cations, when partially substituting Bi in bismuth oxide, produce what appear to be the best low temperature isotropic oxide ion conductors (i.e. the conductivity is independent of direction). It is now vital that we fully characterise these materials in order to:i optimise their properties;ii fully check (and possibly improve) their stability to long term usage at low temperatures;iii explore their potential for real applications;iv explore the possible extension of our observation to other systems.In particular, we need to explore the detailed structure of the materials we have already synthesised, especially the local structure around the ions substituted into the bismuth oxide framework, and the surface properties which are important for applications in real devices. We also need to have a better understanding of the mechanism applicable to the O2- migration in these materials, in order to rationalise the improved conductivity observed. This objective cannot be achieved experimentally, but requires the use of theoretical modelling. The proposal therefore will bring together four high quality research groups from different research centres, each of which will provide unique, internationally leading expertise in the areas necessary to achieve the objectives:Birmingham / synthesis, structure evaluation;Imperial College / surface properties and O2- ion diffusion parameters;Sheffield / conductivity measurements under variable atmospheric conditions;Bath / theoretical simulations to explore the mechanism of O2- migration and provide information on other possible methods to achieve similar, or better, properties.

通常认为，导电的固体通过带电电子在外加电场下的运动来导电，而导电的液体需要带电离子的运动。然而，情况并非总是如此。液态汞也许是表现出金属（电子）导电性的最好例子，还有许多固体的导电性主要是由于离子迁移。因此，这种固体可以显示出与液体电解质类似的性质和应用。通过O2-离子的迁移进行传导的固体的一个重要应用是作为高温固体氧化物燃料电池（SOFC）的电解质，其中电解质将活性电极材料（其可以简单地是O2和H2）分开。其它应用包括O2传导膜，其例如可用于通过使电流通过膜而从不纯源（通常为空气）生产纯氧。这种装置可用于大规模氧气生产或用于便携式装置，例如用于医疗目的。对于效率和技术稳定性，低温操作是一个要求，并且对在低温下显示出高O2传导性的新材料的需求为该提议提供了刺激。我们已经做了一个重要的观察，某些阳离子，当部分取代铋氧化物中的铋，产生什么似乎是最好的低温各向同性氧化物离子导体（即电导率是独立的方向）。现在至关重要的是，我们要充分利用这些材料，以便：i优化其性能;ii全面检查（并可能改善）它们在低温下长期使用的稳定性;iii探索它们用于真实的应用的潜力; iv探索我们的观察可能扩展到其他系统。特别是，我们需要探索我们已经合成的材料的详细结构，特别是取代到氧化铋骨架中的离子周围的局部结构，以及对于在真实的器件中的应用重要的表面性质。我们还需要更好地了解适用于这些材料中O2迁移的机制，以便合理化观察到的电导率提高。这一目标无法通过实验实现，但需要使用理论建模。因此，该提案将汇集来自不同研究中心的四个高质量研究小组，每个小组将在实现这些目标所必需的领域提供独特的、国际领先的专门知识：伯明翰/合成、结构评价;帝国理工学院/表面性质和O2-离子扩散参数;谢菲尔德/可变大气条件下的电导率测量;浴/理论模拟，探索O2迁移的机制，并提供其他可能的方法，以实现类似的信息，或更好的，性能。

项目成果

Defect and transport properties of BiFeO3

BiFeO3 的缺陷和输运特性

• 发表时间: 2010
• 期刊: Advanced Functional Materials
• 影响因子: 19
• 作者: N/a Stokes

Solid-State Materials for Clean Energy: Insights from Atomic-Scale Modeling

用于清洁能源的固态材料：原子尺度建模的见解

• DOI: 10.1557/mrs2009.216
• 发表时间: 2011
• 期刊: MRS Bulletin
• 影响因子: 5
• 作者: Saiful Islam M