Layered LiNi0.8Co0.1Mn0.1O2 has high potential of around 4.2 V and it has a reversible capacity of 200 mAh/g. Therefore, it appears the high theoretical energy density. Due to the above advantages it is widely used in the industry. However, the industrial application of Ni-rich cathode is impeded by the inherent chemical instability. To investigate the correlation between the structure and cycle-life, we made a pouch-cell using the above cathode material and measured in-situ XRD (0.2 C-rate) at 1st, 100th, 200th, and 500th cycle during charge-discharge process at 1.0 C-rate.