Crystal structure analysis of Li-ion battery by laboratory operando X-ray diffraction

Li-ion batteries are preferred energy storage technology for portable electronics, electric and hybrid vehicles. For the large-scale commercialization of electric vehicles and the utilization of renewable energy, the energy storage capacity, cycle life, rate capacity and safety of most commercial batteries still need to be improved. To further improve battery performance it is essential to analyze the reaction mechanism under practical operation for future Li-ion batteries. In this work, the crystal structure of cathode and anode materials in non-equilibrium states during the charge and discharge processes was investigated by laboratory operando X-ray Diffraction (XRD). It was found that the charge and discharge processes differ markedly between the high rate and the low rate. Furthermore, the relationship between the graphite anodes of the different particle sizes and the changes in the crystal structures during charge and discharge process is discussed. (author)