Preparation of Li[Ni 1/3Co 1/3Mn 1/3]O 2 powders for cathode material in secondary battery by solid-state method

Abstract

Employing Li 2CO 3, NiO, Co 3O 4, and MnCO 3 powders as starting materials, Li[Ni 1/3Co 1/3Mn 1/3] O 2 was synthesized by solid-state reaction method. Various grinding aids were applied during milling in order to optimize the synthesis process. After successive heat treatments at 650 and 950 °C, the prepared powders were characterized by X-ray diffraction (XRD) analysis, scanning electron microscopy, and transmission electron microscopy. The powders prepared by adding salt (NaCl) as grinding aid exhibit a clear R ▪ m layer structure. The powders by other grinding aids like heptane show some impurity peaks in the XRD pattern. The former powders show a uniform particle size distribution of less than 1 μm average size while the latter shows a wide distribution ranging from 1 to 10 μm. Energy dispersive X-ray (EDX) analysiss show that the ratio of Ni, Co, and Mn content in the powder is approximately 1/3, 1/3, and 1/3, respecively. The EDX data indicate no incorporation of sodium or chlorine into the powders. Charge-discharge tests gave an initial discharge capacity of 160 mAh·g −1 for the powders with NaCl addition while 70 mAh·g −1 for the powders with heptane.