Synthesis of Overlithiated LiNiO₂ Cathode Materials for Li-Ion Cells

Abstract

The good cycling performance of LiNiO₂ make it an attractive cathode material for Liion cells. It has not achieved, however, the wide commercial application of the more costly LiCoO₂. The main reason of this is the unsatisfactory reproducibility in the preparation of the high stoichiometric products that can yield a large capacity and good cycling stability. Literature data on the effect of the numerous synthesis conditions on the stoichiometry of LiNiO₂ are not very ample and in some cases contradictory. The present paper is an attempt to improve the reproducibility in the synthesis of overlithiated samples. For this purpose it was necessary to prepare about 200 samples and to characterize them by an accurate and reliable XRD method. It was realized that the most accurate Rietveld profile analysis consuming 10–20 h of apparatus time is inappropriate.