Electrode performance of layered LiNi0.5Ti0.5O2 prepared by ion exchange

A layered Li-Ni-Ti oxide including divalent nickel and tetravalent titanium with a Ni2+/Ti4+ ratio of almost 1 was obtained by the ion exchange of a layered Na-Ni-Ti oxide precursor. By using various nickel and titanium sources, we obtained samples with different specific surface areas. Sample with larger specific surface areas had larger first charge capacities. However, a large irreversible capacity and poor cyclability were observed for all the samples when measured at room temperature. However, when we set the ambient temperature at 55 °C, the cyclability improved. This suggests that the lithium diffusion rate strongly affects the electrode performance of layered Li-Ni-Ti oxide. We also employed a first-principles calculation of the LiNi0.5Ti0.5O2/Ni0.5Ti0.5O2 system to evaluate its structural and voltage characteristics.