Facile Redox Synthesis of Layered LiNi1/3Co1/3Mn1/3O2 for Rechargeable Li-Ion Batteries

Abstract

The increasing demand for energy storage devices has motivated the need to find environmentally friendly, high energy density, and cost-effective materials for energy storage and suitable synthesis techniques. In this work, we report a simple and cost-effective chemical route, in which intermediate Ni1/3Co1/3Mn1/3(OH)2 product was primarily prepared using a simple redox synthesis technique at ambient temperature. Lithiation reactions were then performed at higher temperatures to develop the final layered Lix(Ni1/3Co1/3Mn1/3)O2 structure (where x= 1.0 and 1.05). The lithium content was varied in order to analyze the effect of excess lithiation on the structural and electrochemical properties of the layered-type Li(Ni1/3Co1/3Mn1/3)O2 cathode. The XRD studies clearly confirmed the formation of layered-type structures corresponding to hexagonal α-NaFeO2 (space group R-3m). The ICP studies confirmed the stoichiometric chemical composition (Li(Ni0.32Co0.33Mn0.31)O2) of the prepared samples. FE-SEM images revealed that the particle growth occurred when the particles were heated at elevated temperatures of 950°C, and the average particle diameter was around a few micrometers. The electrochemical tests performed versus lithium indicated that competitive specific capacity values were registered for all the prepared cathodes and the capacity retention was impressive on repeated charge/discharge cycling within the potential range of 3.0 – 4.3 V and a current density of 14 mA/g. In particular, the Li(Ni0.32Co0.33Mn0.31)O2 sample demonstrated the highest capacity retention value (~ 99%) after 50 cycles and better rate performances of 104, 91, 76, and 67 mAh/g at higher current densities of 229, 457, 914, and 1429 mA/g respectively.