Three-Dimension Hierarchical Al₂O₃ Nanosheets Wrapped LiMn₂O₄ with Enhanced Cycling Stability as Cathode Material for Lithium Ion Batteries

Abstract

A three dimensional (3D) Al2O3 coating layer was synthesized by a facile approach including stripping and in situ self-assembly of γ-AlOOH. The uniform flower-like Al2O3 nanosheets with high specific area largely sequesters acidic species produced by side reaction between electrode and electrolyte. The inner coating layer wrapping spinel LiMn2O4 effectively inhibits the dissolution of Mn by suppressing directive contact with electrolyte to enhance cycling stability. The rate performance is improved because of the better electrolyte storage of the assembled hierarchical architecture of the 3D coating layer affording unimpeded Li(+) diffusion from electrode to electrolyte. The electrochemical results reveal the as-prepared coated LiMn2O4 sample with the amount of Al2O3 at 1 wt % exhibits superior cycle stability under room temperature even at elevated temperature. The initial specific discharge capacity is 128.5 mAh g(-1) at 0.1 C and retains 89.8% of the initial capacity after 800 cycles at 1 C rate. When cycling at 55 °C, the composite shows 93.6% capacity retention after 500 cycles. This facile surface modification and effective structure of coating layer can be adopted to enhance the cycling performance and thermal stability of other electrode materials for which Al2O3 plays its role.

Improved Electrochemical Properties of LiMn2O4-Based Cathode Material Co-Modified by Mg-Doping and Octahedral Morphology

“…Especially, the octahedral LiMn 1.95 Mg 0.05 O 4 sample can exhibit a higher capacity of 91.8 mAh g −1 at a high cycling rate of 5.0 C. To further explore the high-rate cycling stability, the octahedral LiMn 1.95 Mg 0.05 O 4 samples were cycled at 10 C. The corresponding characteristic discharge curves are shown in Figure 6a. It can be found that the characteristic voltage plateaus in the discharge curves become blurred to a large extent, which agrees with the research result [39,44,45]. Figure 6b presents the cycling performance of the octahedral LiMn 1.95 Mg 0.05 O 4 samples at 10 C. It can show satisfactory retention of 97.5% after 100 cycles with initial capacity of 72.1 mAh g −1 .…”

Improved cycling stability of V2O5 modified spinel LiMn2O4 cathode at high cut‐off voltage for lithium‐ion batteries

“…This blue shift may be contributed to the fact that a little amount of vanadium ions penetrates into the spinel structure on the surface lattice, shortening the average bond length of Mn-O. 50,56 This results to the strengthen of surface stability of the spinel structure, which agreed well with the results obtained from XRD. Additionally, the similar observation from FTIR spectra was also reported for VO x -coated LiMn 2 O 4 spinel nanorod clusters.…”

Fabrication of an LiMn2O4@LiMnPO4 composite cathode for improved cycling performance at high temperatures

“…Coating materials are divided into the following three categories: (1) transition metal oxides, (2) conductive materials, and (3) other active materials. Transition metal oxides, including Al 2 O 3 [7][8][9], ZnO [10,11], SiO 2 [12,13], and TiO 2 [14], act as a physical protection layer on the particle surface of LMOs to prevent or suppress chemical reactions with electrolytes. The cyclability of LMOs at high temperatures is improved by deposition of chemically stable materials, while electrochemically inactive features of oxides exhibiting low ion and electron conductivities lead to a loss of rate or power capabilities [15].…”