Cooperation of Fe ₂ O ₃ @C and Co ₃ O ₄ /C subunits enhances the cyclic stability of Fe ₂ O ₃ @C/Co ₃ O ₄ electrodes for lithium‐ion batteries

Abstract

Summary A Fe2O3@C/Co3O4 hybrid composite anode is synthesized via a two‐step hydrothermal method in which the acetylene carbon black component serves as a conductive matrix and as an effective elastic buffer to relieve the stress from Fe2O3@C and Co3O4/C during the electrochemical testing. The crystallinity, structure, morphology, and electrochemical performance of the composites are systematically characterized. Galvanostatic charge/discharge measurements of Fe2O3@C/Co3O4 present the excellent rate performance and cyclic stability. Its reversible capacity reaches 1478 mAh·g−1 after 45 cycles, and it is equal to 1035 mAh·g−1 after 350 cycles at a current density of 200 mA·g−1. Furthermore, the changes after 30, 45, 60, 90, and 120 cycles are investigated. It is found that the electrochemical performance varies with the morphological change of the electrode surface. Correspondingly, the microstructure, cyclic voltammetry curves, and Nyquist plots significantly change as a consequence of cycling. The results of this study provide an understanding of the increased capacity and excellent cyclic performance of a new anodic material for Li‐ion batteries.

Liquid Processing of Interfacially Grown Iron‐Oxide Flowers into 2D‐Platelets Yields Lithium‐Ion Battery Anodes with Capacities of Twice the Theoretical Value

“…However, after cycling no peaks are visible, which proves that the film is fully amorphous. [ 14,62 ] This is consistent with literature reports showing both the alloy and conversion type materials undergo amorphization processes upon prolonged cycling leading to the formation of amorphous materials, and pulverization induced particle size reductions. [ 12,62–64 ]…”

“…Both sets of CV curves shows similar shapes with anodic peaks at ≈2 V and cathodic peaks at ≈0.7 V. Notably, the anodic peaks are slightly upshifted and both sets of peaks broadened after activation, probably due to the morphological changes during activation. [ 62 ] As the scan rate was changed from 0.1 to 1 mV s −1 a slight increase in the reaction overpotential was observed indicating that the polarization was small, and the electrochemical reaction kinetics improved.…”

Amorphous 2D‐Nanoplatelets of Red Phosphorus Obtained by Liquid‐Phase Exfoliation Yield High Areal Capacity Na‐Ion Battery Anodes

“…After activation, the CV curves are much broader and relatively featureless, possibly due to morphological changes upon activation but also perhaps due to increased double layer nature of the charge storage. [ 84 ] The specific capacitance of the RP/SWCNTs composite electrodes before and after activation was calculated for each scan rate from the area under the CV curve. Figure 5D presents the specific capacitance of the composite electrodes before and after activation as a function of scan rate ranging from 0.1 to 1 mV s −1 .…”

General Construction of 2D Ordered Mesoporous Iron‐Based Metal–Organic Nanomeshes

“…In addition, due to the continuous destruction of the structure, their interface was unstable and then resulted in the fluctuation in the discharge capacity of mFeP‐NM. [ 49,50 ]…”