CAREER: In Situ Observation of Coupled Transport and Degradation in Battery Electrodes

University Of Alabama In Huntsville, Huntsville AL

Investigators

Abstract

PI Name: Nelson Proposal ID: 1454437 Transportation accounts for 25% to 30% of U.S. energy consumption. Electric vehicles are one alternative to reducing fossil fuel consumption for transportation. Electric vehicles require rechargeable batteries that balance the electrical energy storage and power delivery needs, and these batteries must have lifetimes that support affordable cost of ownership. The lithium-ion battery is currently the leading technology for electric vehicle applications. Lithium-ion battery power and energy storage capacity can be enhanced by utilizing battery electrode materials that are structured at the nanoscale using principles of nanotechnology. However, the use of nanostructured electrodes may accelerate electrode degradation that reduces battery life. This research award seeks to understand degradation in nanostructured lithium-ion battery electrodes during charging and discharging under realistic conditions. This will be accomplished by using advanced x-ray imaging techniques to visualize what happens to the battery electrode during operation, which has never been done before. Insights from the proposed research will lead to battery material structures that improve battery performance and reliability. These improvements in turn have potential to extend the range and lifetime of hybrid and electric vehicles. The education and outreach programs associated with this award will provide mechanical engineering undergraduate students with hands-on experiences in energy storage processes. The technical goal of this CAREER award is develop a fundamental understanding of the processes leading to degradation of nanostructured spinel cathodes for Li-ion batteries through in situ three-dimensional (3-D) X-ray imaging techniques during battery charge and discharge. The proposed research will test the hypothesis that nanostructured cathodes for high power lithium-ion batteries exhibit accelerated degradation at elevated temperature due to enhanced metal dissolution from the cathode active material. This hypothesis will be tested by fabricating electrodes with ordered and irregular microstructure, characterizing electrode performance over a range of temperatures, and directly observing 3-D microstructure using X-ray nanotomography. During the course of this research program, new contributions to the fields of electrochemical energy conversion and storage are expected. These contributions include the use of 3-D X-ray material tomatographic imaging to help elucidate the interactions between electrode microstructure and degradation mechanisms, revealing the merits and challenges of nanostructured battery architectures, and generation of a documented set of 3-D microstructural data for lithium-ion battery materials that is correlated to battery performance and degradation through electrochemical testing. The education and outreach programs associated with this CAREER award will provide mechanical engineering undergraduate students with hands-on experiences in energy storage processes. Energy storage experiments developed for undergraduate laboratories will be adapted to provide modules for K-12 teacher training programs in schools that serve under-represented groups in STEM fields, and will also support development of exhibits at the U.S. Space and Rocket Center in Huntsville, Alabama that engage diverse audiences with energy storage topics and concepts.