Structural and Compositional Optimization of the LiNi0.8Co0.2O2 Electrode by New Synthesis Conditions

Abstract

The optimization of Citrate Precursor Method to obtain the LiNi0.8Co0.2O2 oxide from the thermal decomposition of the citrate precursor (NH4)3LiNi0.8Co0.2(C6H5O7) is presented. The optimization procedure consists of both the lithium atmosphere and the reaction time control during the decomposition of the citrate precursor. Were obtained and characterized two kind of the (Li1-xNix)(Ni0.8Co0.2)O2 oxides, with and without optimized synthesis conditions, identified as A and B oxides, respectively. The A and B oxides are characterized by compositional, structural and electrochemical studies. The results showed that is possible to reach the ordered oxide phase at smaller reaction time if the lithium atmosphere is controlled. From the combination of the chemical analysis by ICP and the DRX Rietveld structural refinement it is possible to establish the Li, Ni(II), Ni(III) and Co(III) composition with great accuracy. The resulted structural and compositional transformations have a close relation with technological parameters of the rechargeable lithium battery using Li Ni0.8Co0.2O2 oxide as cathode.