Layered lithium-rich oxide nanoparticles: low-temperature synthesis in mixed molten salt and excellent performance as cathode of lithium-ion battery

Abstract

Layered lithium-rich oxide, 0.5Li2MnO3·0.5LiMn1/3Ni1/3Co1/3O2, is synthesized in a mixed molten salt of KCl and LiCl under 750 °C. Its morphology and structure are characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and nitrogen adsorption and desorption isotherm, and its performances as cathode of lithium-ion battery are investigated by charge–discharge test and electrochemical impedance spectroscopy, with a comparison of the samples synthesized via solid-state reaction. It is found that the resulting product consists of uniform nanoparticles, 50 nm in average, which possesses a well crystallite layered structure although its synthesis temperature is low and thus exhibits excellent cyclic stability and rate capability. The resulting product delivers an initial discharge capacity of 268 mAh g−1 at 0.1 C and has a capacity retention of 82% after 100 cycles at 1 C, compared to the 243 mAh g−1 and 73% for the sample synthesized by solid-state reaction under 900 °C.