(Digital Presentation) Operando x-Ray Emission/Absorption Spectroscopy to Characterize Electronic Structure Changes of Transition Metals in Lithium-Ion Batteries

Abstract

Demand for high-performance rechargeable batteries has driven the development of novel electrodes with high reversibility and energy density. Tracking the change in electronic and local structure is crucial to investigate and improve the stability and performance of these batteries. Advanced characterization techniques allow the user to monitor electronic and local atomic structure changes to better understand the role and behavior of different elements during cycling of electrode material for rechargeable batteries.X-ray Absorption and Emission Spectroscopy allow us to explore such changes in 3d transition metal elements through the process of generation and quenching of core holes in the sample. Operando measurements enable real-time monitoring of electronic structure changes in electrode materials which enable us to capture phenomena which are only kinetically accessible.In this study, the change in electronic structure of transition metals present in electrode materials is explored as a function of lithium removal through XES Kβ1,3feature along with K-edge XAFS using a lab-scale instrument. The choice of electrodes explored in this study considers the degree of oxidation, structure, and mechanism for ion storage. Change in peak and edge positions of Kβ1,3and K-edge feature is utilized to monitor oxidation/spin changes in electrode materials during charge/discharge. Further the magnetic behavior for ex-situ samples prepared by electrochemical delithiation of LCO in the range of 2-10% delithiation is investigated using Kα and Kβ fluorescence (spin sensitive) followed by K-edge XAFS for Cobalt and Oxygen. Figure 1