Crystallographic facet- and size-controllable synthesis of spinel LiNi_0.5Mn_1.5O₄with excellent cyclic stability as cathode of high voltage lithium ion battery

Abstract

We report a novel synthesis of spinel LiNi0.5Mn1.5O4, in which cubic and porous Mn2O3 nanoparticles, obtained from cubic MnCO3, are used as templates to induce the formation of crystallographic facet- and size-defined spinel. This is done to accomplish excellent cyclic stability of the spinel as a cathode of a high voltage lithium ion battery. The uniformly dispersed pores in the template, whose size can be controlled by limiting the annealing time of MnCO3, facilitate the incorporation of lithium and nickel ions and ensure the formation of spinel with a predominant (111) facet, while the spinel inherits the particle size of the template under controlled temperatures. The characterizations from SEM, TEM and XRD confirm the structure and morphology of the precursors and the resulting product. The charge–discharge test demonstrates the excellent cyclic stability of the resulting products, especially at elevated temperatures: capacity retention of 78.1% after 3000 cycles with 10 C rate at room temperature and that of 83.2% after 500 cycles with 5 C rate at 55 °C.