LAUSR

In this study, carboxylic acids, namely concentrated citric acid and ethylene diamine tetra-acetic acid (EDTA) solution, are used as chelators to synthesize Li-rich layered Li1.2Ni0.13Mn0.54Co0.13O2 (LLNMC) by sol-gel method. We investigate the influence of these chelators on the morphology crystal properties and electrochemical performance of LNMC. Based on XRD data, the synthesized materials can be characterized as a combination of two phases, a rhombohedral R-3m phase (LiNi1/3Mn1/3Co1/3O2) and a monoclinic C2/m phase (Li2MnO3), which, according to the stoichiometry, are xLi2MnO3•(1-x)LiNi1/3Mn1/3Co1/3O2 with x = 0.5. The morphology and local structure were studied using electron microscopy (SEM, TEM and HRTEM) and Raman spectroscopy, respectively. A clear evidence for the effect of chelating agent was observed from electrochemical tests carried out by galvanostatic charge-discharge cycling and electrochemical impedance spectroscopy. The sample prepared via EDTA as organic complexing agent exhibits the best electrochemical properties, with higher capacity and rate capability.