Transmission X-ray microscope (TXM) has been proven to be a powerful experimental method for investigation on material systems at particle level especially when energy resolution is feasible and combined with data-mining technique. With this technique, we can monitor chemical compound evolution and their spatial distribution in cathode material during the electrochemical process. More excitingly it shows the possibility to see the emergence of unexpected minor phase which isn’t anticipated in the first place. Furthermore, with the aid of atomic DFT calculation and mesoscale mechanical simulation we could relate the practical performance of material in real cell with the subtle changes inside a particle. In this report by combining these methods at different length scale we offer our own insights on transition metal dissolution and precipitation, variation of chemical composition in different region of a single particle and the behavior of transition metal at different charge voltage. In general, we hope these findings could benefit our understanding on the material evolution in actual electrochemical process.
The work done at Brookhaven National Laboratory were supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the U.S. Department of Energy through the Advanced Battery Materials Research (BMR) Program, including Battery500 Consortium under contract DE-SC0012704. Research conducted at ORNL's Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy.