LiMn₂O₄ Prepared by Liquid Phase Flameless Combustion with F-Doped for Lithium-Ion Battery Cathode Materials

Abstract

LiMn2O4-yFywere synthesized by a novel method named liquid phase flameless combustion reaction with LiNO3, MnAc2.4H2O and LiF as raw materials calcined at 600 °C for 3 h with HNO3as aided oxidant. All samples were investigated by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR) and electrochemical performance. The results show that: all samples have main phase of LiMn2O4with impurity of Mn3O4and the vibrational bands of Mn-O are a little red shift by doping F, which indicated that the F- enter the host structure of LiMn2O4successfully. The electrochemical performance show that the initial discharge capacities of F-doped samples are lower than pristine LiMn2O4, which is 117.7 mAh•g-1. However, the capacity retention of LiMn2O3.96F0.04and LiMn2O3.90F0.10are 73.6% and 74.5%, respectively, which are higher than pristine LiMn2O4, which is only 69.0% after 40 cycles.

Enhancing Lithium Manganese Oxide Electrochemical Behavior by Doping and Surface Modifications

“…Fluorine (F − ) was regarded as a promising dopant, because, due to its lower ionic radius and higher electronegativity, it partially replaces divalent O 2− and decreases the Mn 4+ content [34,95]. By reducing Mn 4+ to Mn 3+ , the amount of electrochemically active Mn 3+ increased, thus, the initial capacity of the fluorine doped spinel was higher than of aluminum doped LMO, synthesized under similar conditions [95].…”

“…Two main strategies have been employed to diminish LMO's disadvantages: structure doping (cations [31,32], anions [33,34] or multiple ions [29,35,36]) and surface modification of the particles [37][38][39]).…”