Proton conductivity near room temperature in hydrated pyrochlore-derived materials

质子传导氧化物陶瓷的研究主要集中在具有钙钛矿结构的材料上，这些材料可用作在400 °C以上温度下工作的燃料电池的电解质。用于其他电化学应用（例如，作为在室温或略高于室温下操作的电化学机械致动器）的高性能质子传导陶瓷材料目前不可用。该项目的主要目标是确定和优化一种用于250 °C以下的高性能质子传导材料。我们将重点关注具有无序烧绿石结构的材料，其一般组成为A2 B2 O 7，其中A = Sc、Y或镧系元素，B = Zr、Ce或Hf。与钙钛矿结构的质子导体相比，无序的焦磷酸盐受到的关注相对较少，尽管它们对CO2具有高的化学稳定性。通过原子模拟技术和宏观及微观实验研究的明智结合，我们将：a）推导出这些材料中质子导电性的综合模型，并使用它来预测所需的性能; B）开发制备和水合这些材料的陶瓷和薄膜的协议; c）测量和理解它们的导电性的性质，以及它们的电化学稳定性窗口; d）确定组合物，包括使质子传导率最大化的可能的掺杂剂。在更高的层次上，该项目将深化质子导体领域的基础知识，以及与高温超导体相关的结构中的有序-无序转变。除了质子导体的传统应用外，该项目还将为新兴的固态化学电子学领域做出贡献，从MEMS到适应性表面和Si集成质子电池。

Research on proton-conducting oxide ceramics focuses strongly on materials with the perovskite structure that can be used as the electrolyte in fuel cells operating at temperatures above 400 °C. High-performance, proton-conducting ceramic materials for other electrochemical applications (e.g. as an electrochemical mechanical actuator operating at room temperature or just above) are currently not available. The primary objective of this project is to identify and optimise a high-performance, proton-conducting material for use below 250 °C. We will focus on materials with a disordered pyrochlore structure, with the general composition A2B2O7, where A = Sc, Y or a lanthanide, and B = Zr, Ce or Hf. In contrast to the perovskite-structured proton conductors, disordered pyrochlores received relatively little attention, despite their high chemical stability to CO2. Through a judicious combination of atomistic modelling techniques and macroscopic and microscopic experimental studies, we will: a) derive a comprehensive model of proton conductivity in these materials and use it to predict the desired properties; b) develop protocols to prepare and hydrate ceramics and thin films of these materials; c) measure and understand the nature of their conductivity, and their electrochemical stability window; d) identify the compositions, including possible dopants that maximize proton conductivity. At a higher level, the project will deepen fundamental knowledge in the field of proton conductors and also of order-disorder transitions in pyrochlore-related structures. In addition to the traditional applications of proton conductors, this project will contribute to the emerging field of solid-state chemotronics ranging from MEMS to adaptable surfaces and to Si-integrated proton batteries.