Electrochemical properties of Li[(Ni0.5Mn0.5)1-xCox]O2 for high voltage application in Li-ion battery

Abstract

Due to fast development of portable devices, they need lithium-ion batteries which possess much higher volumetric energy density. There are two way to increase the volumetric energy density; i) loading more amount of active materials on electrodes; ii) raising the upper cut-off voltage limit. The first term seems to be easir way because it is obvious that loading more amount of active material exhibits much higher capacity in the limited cell volume though the upper cut-off voltage is kept to 4.2V versus C. In this case safety concern would be arisen due to high reactivity of Li1-xCoO2. Therefore, raising the cut-off voltage would be one possible way to the better way to improve the volumetric energy density. However, if one select LiCoO2 as the positive electrode material, it would be not work so well because it has been know that exthothermic reaction of highly delithiated Li1-xCoO2 is very reactive, accompanying by oxygen release, and dissolution of co element is quite critical at higher voltage.