Investigation into Surface-Modified Electrode Materials for Li-Ion Batteries

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NON-TECHNICAL DESCRIPTION: Batteries are now more ubiquitous than ever, powering our laptops, smartphones, and other portable electronic devices. Other applications include medical devices (e.g. portable defibrillators) as well as electric cars. The performance and capacity of batteries are greatly influenced by the properties of their electrode surfaces; surface modifications are widely used to mitigate electrode problems and thus enhance battery performance. Although enormous effort has been devoted to the study of electrode surfaces, a detailed understanding of the electrochemistry on these surfaces and the mechanisms by which surface modifications enhance performance is still lacking. The motivation for this project is to utilize unique spectroscopic tools to directly probe electrode surfaces under in operando conditions (that better replicate real-world battery operating conditions). The results of the project will be widely disseminated through peer-reviewed publications, and the new scientific knowledge is expected to have a significant impact on the rational design of electrode surfaces and interfaces for improved battery performance. The new knowledge is also being incorporated into courses offered at Georgia Tech, and eventually at other universities as well.TECHNICAL DETAILS: The feasibility of using Raman spectroscopy to directly probe many important surface species and new phases relevant to electrode reactions has been demonstrated. In this project, in operando surface enhanced Raman spectroscopy (SERS) is applied to well-designed model systems (e.g. LiMn2O4-based electrodes) in order to gain deeper insights into electrode surfaces. The surface structure and composition of battery electrodes are directly correlated to their effects on battery capacity, rate capability, cycling life, and capacity retention in order to unravel the mechanisms of performance enhancement through surface modification and to provide scientific guidelines for rational design of superior electrode materials and structures. With rising demand for better battery life and performance for a variety of applications (portable personal electronics, medical devices, electric cars, etc.), this project seeks to better understand the electrode surfaces that underpin battery performance. One graduate student and one to two undergraduate students are working as research assistants on the project; the students are gaining valuable experience with cutting-edge in operando characterization techniques.