Operando Scanning X-ray Diffraction Imaging of Li ionic order in high-voltage LiMn1.5Ni0.5O4 cathode materials

High voltage spinel cathode materials such as LiMn1.5Ni0.5O4 (LMNO) are considered to be the next step in the evolution of lithium-ion battery (LIB) technology. The main motivations for studying these materials are their relatively large theoretical energy density, fast charging capabilities and low material costs. However, the charge/discharge phase transitions of these materials are complex, and poorly understood, which currently limits their rechargeability and commercial viability. Operando Scanning X-ray Diffraction microscopy (SXDM) will allow us to follow these phase transitions at the scale of single nanocrystals, and determine the link between cationic ordering, strain, mosaicity, and the dynamics of the phase transitions during battery (dis)charging. This experiment is aimed at studying the spatial distribution of reversible redox processes and lithium deintercalation occurring in single crystal particles. The obtained data on strain transformation would give us valuable information about variations of lithium ionic order and phase evolution at the nanoscale, and will allow to image heterogeneities in way inaccessible by any other method.