Enhanced Electrochemical Properties of Surface Modified LiMn₂O₄by Li-Fe Composites for Rechargeable Lithium Ion Batteries

Abstract

The surface modified LiMn2O4 materials with Li-Fe composites were prepared by a sol-gel method to improve the electrochemical performance of LiMn2O4 and were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), and transmission electron microscopy (TEM)-EDS. XRD results indicate that all the samples (modified and pristine samples) have cubic spinel structures, and XRD, XPS, and TEM-EDS data reveal the formation of Li(LixFexMn2-2x)O4 solid solution on the surface of particles. For the electrochemical properties, the modified material demonstrated dramatically enhanced reversibility and stability even at elevated temperature. These improvements are attributed to the formation of the solid solution, and thus-formed solid solution phase on the surface of LiMn2O4 particle reduces the dissolution of Mn ion and suppresses the Jahn-Teller effect.

Investigation of Characteristics of CV Properties in LiMn₂O₄ by Primary Nanoparticle Analysis

“…The XPS spectra showed Mn2p 3/2 feature at 642.6 eV on the both active materials, and this values was consistent with other reports. 8 Further, the O1s peak was observed around 529.8 eV of binding energy on the both active materials. This finding indicated that the binding energies of Mn2p 3/2 and O1s were same on the surface of the NS-LMO and MS-LMO.…”

An Investigation of LiFePO4/Poly(3,4-ethylenedioxythiophene) Composite Cathode Materials for Lithium-Ion Batteries

“…Each EIS curve consists of two semicircles representing the resistance of the surface electrolyte interface (SEI) film in the high frequency and the charge-transfer resistance in the medium frequency. [21][22] The value of each resistance is determined using the equivalent circuit shown in the inset of Figure 4. The LiFePO4/5 wt % PEDOT electrode exhibits significantly lower charge-transfer and SEI film resistances (20.73 and 5.296 Ω) than pristine LiFePO4 (35.02 and 6.397 Ω).…”