Highly enhanced lithium storage capability of LiNi0.5Mn1.5O4 by coating with Li2TiO3 for Li-ion batteries

Abstract

A uniform and thin Li₂TiO₃ layer with various amounts was coated on the surface of nanostructured LiNi_0.5Mn_1.5O₄ (LNMO) materials by in situ hydrolysis of tetrabutyl titanate (TBOT) followed by the lithiation process. The morphology and structure of the samples were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM) with an energy-dispersive X-ray spectroscope (EDS). Electrochemical tests illustrate that Li₂TiO₃ as a Li⁺-conductive coating layer remarkably improved the rate and cycling performance of the LNMO spinel cathode. Particularly, the 3 wt% and 5 wt% Li₂TiO₃-surface modified samples deliver high discharge capacities of 95 mA h g⁻¹ and 90 mA h g⁻¹ even at a high current density of 5 C, while the bare one only has a discharge capacity of 70 mA h g⁻¹. At a current density of 1 C at elevated temperature, the 3 wt% and 5 wt% Li₂TiO₃-surface modified LNMO samples show excellent cyclability. After 50 cycles, the capacity retention of 3 wt% and 5 wt% Li₂TiO₃ modified LNMO is 88.1% and 94.1%, while only 77.1% for the bare sample.