A study of the electrochemical lithium intercalation behavior of porous LiNiO2 electrodes prepared by solid-state reaction and sol-gel methods

The electrochemical lithium intercalation behavior of porous LiNiO2 electrodes prepared by solid-state reaction and sol-gel methods is investigated by using X-ray diffractometry (XRD), a galvanostatic intermittent charge-discharge experiment, electrochemical impedance spectroscopy(EIS), and a charge-discharge cycling test. The ultrafine LiNiO2 powder is prepared by the sol-gel method in order to overcome the disadvantage of the conventional solid-state reaction method. From the results of XRD, the layered LiNiO2 phase proves to be stable above 400°C. The conventional oxide electrode suffers a larger capacity loss, a greater instantaneous IR drop during the first intermittent discharge, and a smaller chemical diffusivity than the gel-derived electrode. The results are discussed with respect to the marked cation mixing effect in the former electrode. Furthermore, the charge-discharge cycling test shows that the cell Li/organic electrolyte/gel-derived LiNiO2 electrode displays improved performance, i.e., an initial specific capacity of 150 Ah kg−1 and a specific energy density above 500 Wh kg−1.