Synthesis and Electrochemical properties of Li(Ni1/3Co1/3Mn1/3)O2 using co-precipitation

Abstract

Recently, attempts have been made to add other components to nickel hydroxide used as the starting material for production of lithium nickel oxide, for the pupose of including additional components with lithium nickel oxide for use as the positive electrode active material of lithium ion secondary batteries in order to improve their charge/discharge cycle properties and high temperature stability. However, with the conventional method such as solid-state method etc, it has been difficult to spherical particle containing cobalt, manganese as the additional components. the above-mentioned conventional production process give particles that are inadequate for use in the positive electrode of a lithium ion secondary battery, and thus it has became an important goal to develop high density nickel hydroxide with a high cobalt and manganese content that exhits a stable high utilization rate at high temperature and low cycle deterioration the spherical (Ni1/3Mn1/3Co1/3)(OH)2 were prepared by adding an s NH4OH solution as a chelating agent, and an NaOH solution as a pH-adjusting agent, to an aqueous mixed solution containing mixed sulfate solution containg nickel, manganese, cobalt. The influence of various conditions in spherical (Ni1/3Mn1/3Co1/3)(OH)2 is pH, temperature, feeding rate, concentration of metal salt, additive NH4OH, reactor-type. Experimental result shows that several factor such the concentration of NH4OH, pH, stirring speed. The Spherical Li[Ni1/3Mn1/3Co1/3]O2 powders is prepared easily synthesized by firing LiOH·H2O and spherical (Ni1/3Mn1/3Co1/3)(OH)2 without grinding in air at 1000oC. The tap-density is 2.2 g cm-3 Li/ Li[Ni1/3Mn1/3Co1/3]O2 cells have very smooth and monotonous voltage profile and exhibit similar voltage profile. Li[Ni1/3Mn1/3Co1/3]O2 cells as a function of cycle number between 2.8 and 4.4 V at a constant current density of 0.2 mA cm-2 (20 mA-1 and 30℃, The measured discharge capacities are 170mAh g-1 without capacity fading. The spherical Li[Ni1/3Mn1/3Co1/3]O2 powders with the high tap-density and high specific capacity is a very candidate to be used in the lithium secondary batteries with high energy density.