Layered LiNi1-xCoxO2 is one of the promising cathode materials for Li-ion battery application. However, the Ni rich cathode materials exhibit low capacity and bad capacity retention. This is due to factors such as disorder and structural instability when Li is removed during charge-discharge. Overlithiation of cathode materials is expected to improve the cation ordering and structural stability. Good cation ordering will increase the battery capacity. During charge-discharge, the irreversible Li+ loss can be replaced to a certain extent by the interstitial Li+ ions in the lattice of the LixNi0.8Co0.2O2 material. This helps reduce capacity fading of the cathode materials. In this work the overlithiation of LiNi0.8Co0.2O2 is done by interstitially doping Li+ in the LiNi0.8Co0.2O2 materials producing Li1.05Ni0.8Co0.2O2 and Li1.1Ni0.8Co0.2O2. Results showthat the performance of the overlithiated LiNi0.8Co0.2O2 materials is better than pure LiNi0.8Co0.2O2.
Charge–discharge behavior of Sn–Ni alloy film electrodes in an intermediate temperature ionic liquid for the electrolyte of a sodium secondary battery