Studies of the Local Structure in LixNi0.7Co0.3O2 (0.5≤x≤1.0) Cathode Materials

Among the LixNi1-yCoyO2 system, LiNi0.7Co0.3O2 is being considered one of the best cathode materials due to its small volume cell expansion upon charge-discharge cycling. In order to study the modifications of structural and physical properties occurring in the cathode materials during charge, different LixNi0.7Co0.3O2 samples ( 0.5 >= x >= 1.0) were prepared by electrochemical lithium deintercalation in non-aqueous cells. During the first charge of the Li//LixNi0.7Co0.3O2 cell, the structural change in the cathode lattice was followed by both x-ray powder diffraction and FTIR spectroscopy at room temperature. A good correlation is found between XRD data and the local environment of the host lattice.