LiMn2O4 spinel is an attractive compound as a cathode material in lithium-ion batteries, due to its economical, environment, and safety advantages over LiCoO2. LiMn2O4 adopts the spinel structure with the space group Fd3 hm, in which the Li and Mn occupy the 8a tetrahedral and 16d octahedral sites of the cubic close-packed oxygen ions framework, respectively. However, LiMn2O4 tends to exhibit c...

LiMn2O4 has been studied using magic-angle-spinning nuclear magnetic resonance (MAS NMR). 1D MAS NMR shows three Li resonances assigned to different crystallographic sites. At low temperatures an extra peak appears, indicating charge ordering of Mn3+ and Mn4+. Direct observation of the lithium dynamics was possible using rotor-synchronized 2D exchange NMR. A millisecond time scale exchange of l...

A series of Mn-based intercalation compounds have been applied as the cathode materials of Li-ion batteries, such as LiMn2O4, LiNi1−x−yCoxMnyO2, etc. With open structures, intercalation compounds exhibit a wide variety of thermodynamic and kinetic properties depending on their crystal structures, host chemistries, etc. Understanding these materials from thermodynamic and kinetic points of view ...

We demonstrate the ability to apply electron energy loss spectroscopy (EELS) to follow the chemistry and oxidation states of LiMn2O4 and Li4Ti5O12 battery electrodes within a battery solvent. This is significant as the use and importance of in situ electrochemical cells coupled with a scanning/transmission electron microscope (S/TEM) has expanded and been applied to follow changes in battery ch...

The benefit of LiFePO4 as a cathode material in rechargeable batteries has sparked considerable research interest. The 2015 Research Experience for Undergraduates (REU) in Physics at Howard University provided an opportunity to examine the electrical conductivity of carbon-coated LiFePO4.4-Point Probe resistivity testing shows that the cathode has an electrical conductivity value of σ=1.45 x 10...

Herein, a comprehensive study of electrochemical performances the combined effect fluorinated additives; fluoroethylene carbonate (FEC); and tris(2,2,2-trifluoroethyl) phosphite (TTFP) or 2,2,2-trifluoroethyl methyl (TFEMC) as co-solvent, on Graphite//LiMn2O4 cells cycled at high potential is reported. On one side, each additive has specific function, FEC dedicated to negative electrode TTFP op...

With an 11Ah LiMn2O4 battery as the object of study, through disassembling after normal charge and discharge well over-charge over-discharge, using such methods x-ray diffraction scanning electron microscope, this study explores micro-changes that happened to material for anode cathode lithium provides measures prevent batteries from discharge, so avoid potential safety problems during use batt...