Fundamental Understanding on the Role of Structural Defects on Lithiation of Nanoscale Transition Metal Oxides

全球范围内正在进行广泛的研究，以寻找更好的锂离子电池材料，以增加其能量和功率。过渡金属氧化物作为锂离子电池的电极具有上级性能，但是由于对它们的电化学性能缺乏了解，阻碍了它们的商业应用。 特别是，需要更好地研究局部原子结构和化学的变化，以便适当地设计它们用于可充电电池应用。在材料研究部固态和材料化学计划的支持下，该项目将致力于解决这一缺点。首席研究员计划在高分辨率电子显微镜内研究电化学电池反应，使成像达到原子水平。有了这种能力，锂离子运动内的电池电极可以研究在存在的结构defects.Technical AbstractNanoscale过渡金属氧化物（TMO）的锂离子电池是有前途的材料。这些材料通过转化反应进行操作，并与高能量密度相关。这些材料非常容易受到合成过程中产生的结构缺陷的影响，这些缺陷会改变锂离子的路径并影响其电化学性能。这项研究活动的目的是了解潜在的原子机制，结构缺陷，如异质界面和位错影响TMO的锂化行为。为了实现这一目标，纳米级TMO在原子分辨率透射电子显微镜内进行真实的时间电化学锂化。该项目有望更好地了解结构缺陷附近局部应变和电子结构的演变及其对锂离子通道的影响。此外，在异质界面和位错的存在下，可以研究转化反应相的结构演化。

Non Technical AbstractExtensive research worldwide is underway to find better materials for Li-ion batteries in order to increase their energy and power. Transition metal oxides offer superior performance as electrodes for lithium-ion batteries; however, the progress toward their commercial use has been hindered due to lack of understanding of their electrochemical performance. In particular, variations in local atomic structure and chemistry need to be better investigated in order to properly design them for rechargeable battery applications. With support from the Solid State and Materials Chemistry program in the Division of Materials Research, this project will work to address this shortcoming. The principal investigator plans to study the electrochemical battery reactions inside high-resolution electron microscopes enabling imaging down to atomic level. With this capability, lithium-ion movements inside the battery electrodes can be investigated in the presence of structural defects.Technical AbstractNanoscale transition metal oxides (TMO) are promising materials for lithium-ion batteries. These materials operate through conversion reactions and are associated with high energy densities. These materials are highly vulnerable to structural defects produced during synthesis that can alter lithium ion pathways and affect their electrochemical performance. The objective of this research activity is to understand the underlying atomistic mechanisms by which structural defects such as heterointerfaces and dislocations affect the lithiation behavior of TMOs. To meet this goal, nanoscale TMOs are subjected to real time electrochemical lithiation inside atomic-resolution transmission electron microscopes. This project is expected to yield better understanding on the evolution of localized strain and electronic structure at the vicinity of structural defects and their effect on lithium-ion pathways. In addition, the structural evolution of conversion reaction phases can be investigated in the presence of heterointerfaces and dislocations.