In situ energy dispersive X-ray diffraction study of LiNi0.8Co0.2O2 cathode material for lithium batteries

The investigation of structural changes of intercalation materials during cycling is of primary importance to understand the factors that limit their cyclability. In particular in-situ measurements, allowing the simultaneous acquisition of structural and electrochemical data, consent to directly correlate the cycling performance of the material under test to its structure evolution and vice versa. The energy dispersive X-ray diffraction (EDXD) technique has been applied to the study of the structural evolution of LiNi0.8Co0.2O2 during several charge-discharge cycles performed with increasing anodic Limits. This way of monitoring the effect of Li ions intercalation-deintercalation process on the host materials lattice parameters proved to be a valid alternative to the traditional angle dispersive X-ray diffractian (ADXD) method, solving some of its problems, first of all the question of the X-ray absorption. The results described in this paper confirm what reported in previous literature works based on in-situ ADXD and deepen the study of the LiNi0.8Co0.2O2 structural changes, with large oversampling and good statistical accuracy, extending the investigation to the first 7 cycles with increased anodic limits approaching full delithiation.