Disordered Spinel Lini0.5Mn1.5O4 Cathode With Improved Rate Performance For Lithium-Ion Batteries

Abstract

The high voltage LiNi0.5Mn1.5O4 cathode with a disordered spinel structure is synthesized by a glycine- assisted low-temperature reaction follows by a thermal treatment at 750 C, 850 C, and 950 C for 12 h. Glycine is used as a chelating agent for the first time to build required environment for shaping the precursor of LiNi0.5Mn1.5O4 materials. The microstructure and morphology of the LiNi0.5Mn1.5O4 product are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, Brunauer-Emmett-Teller, and transmission electron microscopy. The sample prepares at 750 C reveals small particles with well-defined crystals as confirmed by electron microscopy. Electrochemical results demonstrate that LiNi0.5Mn1.5O4 electrode anneal at 750 C (compare to other two samples) delivers the highest reversible capacity of 110 mAh g 1 at 0.2C after 100 cycles with good rate capability. The enhanced electrochemical performance could be attributed to the smaller particle sizes as well as welldefined crystals which provide a directional and shorter diffusion path length for Li+ transportation within the crystals.