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In Situ TEM Study of Anode Nanomaterials for Energy Storage


EMSL Project ID
48266

Abstract

The goal of this project is to understand the physical and chemical changes, along with interfacial charge transfer, that occur in advanced anodes in lithium ion batteries (LIBs). For example, silicon (Si) and germanium (Ge) nanomaterials are some of the most promising replacements for the standard graphite anodes in LIBs because of their much higher lithium storage capacity. However, the chemical and physical changes that occur during cycling include significant volume expansion and contraction and solid-electrolyte-interphase (SEI) layer formation chemistry that differs significantly from graphite. Using in situ transmission electron microscopy (TEM), structural and interfacial changes that occur during electrochemical cycling can be directly observed. With in situ TEM, unexpected phenomena have already been discovered in Si and Ge nanomaterials, including reversible mesopore formation and annihilation, which profoundly influences SEI layer chemistry and stability and how to design protective coatings--new guidelines can be developed for improving Si and Ge anode performance. The proposed work combines the capability at UT Austin to design and produce Si and Ge nanomaterials with tailored size, morphology, composition and interfaces, with the in situ TEM facilities and expertise at PNNL, to uncover new understanding about these materials systems. The proposed work will focus on understanding: 1) failure mechanisms of Si and Ge anodes in LIBs, especially structures related to degradation during cycling; 2) electrochemical reactions and associated charge transfer mechanisms, including the processes that occur at interfaces; and 3) SEI formation and its role in improving anode performance.

Project Details

Project type
Large-Scale EMSL Research
Start Date
2014-10-01
End Date
2016-09-30
Status
Closed

Team

Principal Investigator

Brian Korgel
Institution
University of Texas at Austin

Team Members

Emily Adkins
Institution
University of Texas at Austin

Xiaotang Lu
Institution
University of Texas at Austin