2-14.High-throughput experiments under Electron-beam: exploring mesoscopic structure-property relationship for energy materials

Hui Gu
School of Materials Science Engineering & Materials Genome Institute, Shanghai University

Abstract: The cross-scale issues and effects are either simplified or largely omitted in the study of “structure-property” relationship for materials, thanks to the belief or precondition that this is uniform from microscopic to macroscopic scales. It is even more so for high-throughput experiments which are overwhelmed by compositional variation hence limited to average or common structural features. For compound materials which are more subject to doping chemistry and kinetic processes, the structural and compositional inhomogeneity at mesoscopic scale often becomes a predominant effect. This constitutes a further relationship of “microstructure-(dopant)distribution-performance”, and it could provide a different basis for application/service oriented materials designing and optimization. Scanning electron microscope can develop into a suitable cross-scale platform for structural and chemical study centered on mesoscopic scale, since the interactions between the electron beam and the probed matter volume can be controlled or characterized, and integrated, in situ or cross-scale experiments can all be realized and subsequently configured into high-density data systems, starting from the microstructure features of structural and functional compounds. Modern scanning beam can general several imaging modes for a given structural or chemical inhomogeneity, and multiple structural, chemical spectroscopies could further increase the depth of structure-property relations at the (sub)-micron to nanometer scales. In this talk, I would like to demonstrate with two case studies of energy materials the effectiveness of SEM platform, especially in quantitative approaches to reveal novel data systems at mesoscopic scale. In a solid state electrolyte for lithium-ion battery, the controlled electron beam can inquire the mobility of lithium ions in the electrolyte by prompting their expulsion from different regions of microstructure with controlled irradiation. Correlation of local mobility with local chemical inhomogeneity helps to understand the growth behavior of Li dendrites especially on growth rate. For a thermoelectric material, high-throughput microstructure characterization can be conducted on quasi-continuous-compositional variation system made by a high-throughput processing for bulk compounds. The macroscopic system design, micron-scale phase and grain evolution, nanometer-scale diffusional and interfacial behaviors, could be synergistically integrated into a multi-scale data-collection framework, which is ready to expand into a

phenome-driven study of structure-property relationship.
Keywords:Scanning electron microscopy platform; Mesoscopic structure-property relationship; Solid-state electrolytes; Thermoelectric materials

扫描电子束下高通量实验:能源材料介观尺度结构-性能关系探索

顾辉
上海大学 材料科学与工程学院、材料基因组工程研究院

摘要: 材料“结构-性能”关系研究常简化其尺度效应或跨尺度特征，集约式的高通量实验则更 容易局限于平均结构特征或单一的结构层次。对化合物材料体系而言，因掺杂及其动力学过程 产生的结构-成分不均匀性，构成介观尺度“微结构-成分分布-性能”关系，这也是应用/服役 性能优化、调控的基础。扫描电镜中对电子束调制并进行集成、原位或组合表征实验，可获得 材料微结构特性、电子-物质作用等多种类、高密度数据体系。扫描电子束优势在于多种模式成 像，可直观获得多种微纳结构的特征;进一步的定量化行为规律研究并与各种谱仪分析结合， 可探索能源材料在介观尺度下的新型“结构-性能”关系。在锂离子电池固态电解质材料中，电 子束辐照强度及方式的改变可诱导锂离子的析出，将其行为特征参数化并解析出锂离子在电解 质内的多种迁移行为。结合掺杂物在电解质微结构中的特征分布规律，进一步获得对迁移率的 调控规律，并为锂枝晶形成原理及生长速度的解析提供新的可能机理。在热电材料体系中，结 合准连续成分制备方法，高通量微结构表征实验不但可系统性呈现固溶成分与微结构的协同演 变过程，还可进一步推动扩散通道及界面反应等定量过程解析，从而获得不同动力学模式的竞 争与抑制机制，为热电性能的提升提供不同的介观微结构研究框架。与组合芯片式、原位集成 式的高通量实验“范式”相对比，这种基于扫描电镜平台、更为“立体化”的表征平台研究模 式，适合于广泛的多元功能材料体系，可与高通量计算及数据挖掘形成更紧密的关系，并有望拓展或延申到服役行为的体系性研究，从而实质性拓展材料基因组技术及工程的发展。 关键词:扫描电镜表征;介观微结构数据;固体电解质;热电材料