Post-mortem and operando Bragg coherent diffraction imaging of degradation in high-voltage LiMn1.5Ni0.5O4 cathode materials

High voltage spinel cathode materials such as LiMn1.5Ni0.5O4 are considered to be the next step in the evolution of lithium-ion battery technology due to their high energy density, fast charging capabilities, low material costs and the absence of Co. However, this material widespread use is hindered by its significant degradation problem in particular capacity fade due to Mn dissolution from the surface of the particle. Both operando and post mortem BCDI studies are very well suited to study this phenomenon since they will allow to gather structural information on the strain gradients inside the particles. We expect BCDI to give us insight into the interfacial reactions between Jahn-Teller distorted surface lattices and the electrolyte that is responsible for the capacity fade in LMNO. Moreover, the operando BCDI data on strain transformation inside a single particle would give us valuable information about the change of lithium ionic order and phase evolution at the nanoscale.