Collaborative Research: Synthesis, Structural Characterization and Electrochemical Studies of Framework Substituted Silicon, Germanium and Tin Clathrates

非技术摘要：晶体材料的结构完整性是一个重要的属性，可以极大地影响其在实际应用中的能力。对于电化学能量存储装置，日常操作涉及离子的电化学插入和提取，这通常伴随着可能导致材料塌陷的较大结构转变。因此，为了实现未来的储能需求，有必要寻找新的电极材料。包合物是一类具有笼状结构的材料，其可以自然地保持客体离子，这是可以在能量存储应用中利用的特征。然而，笼形物结合布置中的不同特征可能影响其机械完整性。该项目的主要目标是了解这些材料的电化学特性，在电化学插入客体离子后笼形物的结构如何变化，以及开发新的合成路线以获得笼形物。从这个项目的结果，使新的知识之间的复杂关系的笼形物？技术摘要：本项目的目标是：（1）研究锗和锡笼形物的电化学和结构特性，使用第一原理计算和详细的结构表征来理解电化学获得的结构;和（2）从新的前体合成新的含锂离子的笼形物。该项目采用协调一致的方法，结合了合成，结构和电化学表征以及研究人员的理论专业知识。该研究有助于更好地理解笼形物结构与其物理性质、电化学特性和相稳定性之间的关系。这些成就可能导致更高能量密度的锂和钠电池。这些研究还有助于建立固态化学的预测能力，建立原子为什么以及如何组装和形成具有所需电化学性质的新化合物和结构的新想法。这些材料的调查涉及两所大学（亚利桑那州立大学和特拉华州大学）和三个不同的部门（材料科学，化学和物理）之间的合作，这使学生接触到多学科的研究。从中学到大学的学生都参与了外联和教育活动，重点是招收女生进入科学和工程专业，改善学生在大学本科入门课程中的学习和参与。

Nontechnical Abstract:The structural integrity of a crystalline material is an important property that can greatly influence its ability to be utilized in practical applications. For electrochemical energy storage devices, daily operation involves the electrochemical insertion and extraction of ions, which is often accompanied by larger structural transformations that may cause the material to collapse. Hence, the search for new electrode materials is necessary in order for future energy storage demands to be realized. Clathrates are a class of materials with cage-like structures that can naturally hold guest ions, a feature that may be exploited in energy storage applications. However, different features in the clathrate bonding arrangement may affect its mechanical integrity. Key objectives of this project are to understand the electrochemical characteristics of these materials, how the structure of the clathrate changes upon electrochemical insertion of guest ions, and the development of new synthetic routes to obtain clathrates. Results from this project enable new knowledge on the intricate relationships among the clathrates? structures and their physical properties, electrochemical characteristics, and structural stability.Technical Abstract:The objectives of this project are: (1) to investigate the electrochemical and structural properties of germanium and tin clathrates using first principles calculations and detailed structural characterization to understand the electrochemically obtained structures; and (2) to synthesize new clathrates containing lithium ions from novel precursors. The project uses a concerted approach combining the synthetic, structural and electrochemical characterization, and theoretical expertise of the investigators. The research enables a better understanding of the relationship between the clathrate structure and its physical properties, electrochemical characteristics, and phase stability. These achievements could lead to higher energy density lithium and sodium batteries. The studies also help to build up the predictive power of solid-state chemistry, establishing new ideas of why and how atoms assemble and form new compounds and structures with the desired electrochemical properties. Investigation of these materials involves a collaboration between two universities (Arizona State University and University of Delaware) and three different departments (materials science, chemistry, and physics), which exposes students to multidisciplinary research. Outreach and educational activities engaging students ranging from the middle school to undergraduate levels, with an emphasis on recruiting females into science and engineering and improving student learning and engagement in introductory undergraduate classes.