Structural and Electrochemical Properties of Li[Ni0.5Mn0.5]1-xCoxO2 Cathode Materials

Abstract

Due to high cost of LiCO2, a commonly used cathode material in commercial rechargeable lithium batteries, much effort has been made to develop cheaper cathode materials than LiCO2. To this end, LiNiO2 and LiMnO2 have been studied extensively as possible alternatives LiCO2 [1-2]. However, LiNiO2 and LiMnO2 have been problem for practical application. Recently, various attempts have been made to enhance the electrochemical performance of LiNiO2-LiCoO2-LiMnO2 solid solution [3,4]. Among them, LiNi1/3Co1/3Mn1/3O2 has been suggested as the most promising an alternative to LiCoO2 since Ni, Co and Mn can substitute each other to form a solid solution of any percentage without disturbing the layer structure. Recently, we reported on the synthesis and electrochemical properties of Li[Ni1/2Mn1/2]O2 powders prepared by an ultrasonic spray pyrolysis method [5]. The ultrasonic spray pyrolysis is a useful method for the synthesis of high-purity, homogenous powders. In this study, we synthesized of Li[Ni0.5Mn0.5]1-xCoxO2 (0-0.33) materials by a spray pyrolysis method. The Li[Ni0..5Mn0.5]1-xCoxO2 compounds are considered to be a solid solution of LiNiO2, LiMnO2, and LiCoO2. We investigate the effect of Co-substituted amount in the Li[Ni0..5Mn0.5]1-xCoxO2 materials on structural and electrochemical properties.