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

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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.