3D Starfish‐Like FeOF on Graphene Sheets: Engineered Synthesis and Lithium Storage Performance

Abstract

To address the problemsa ssociated with poor conductivity and large volumev ariation in practical applications as ac onversion cathode, engineering of hierarchical nanostructured FeOF coupled with conductive decoration is highly desired,y et rarely reported. Herein, 3D starfish-like FeOF on reduced graphene oxide sheets (FeOF/rGO) is successfully prepared, for the first time, through ac ombination of solvothermal reaction, self-assembly,a nd thermal reduction. Integratingt he structuralf eatureso ft he 3D hierarchical nanostructure, which favorably shorten the path for elec-tron/ion transport and alleviate volumetric changes, with those of graphene wrapping,w hich can further enhance the electricalc onductivity and maintain the structural stability of the electrode, the as-preparedFeOF/rGO composite exhibits as uperior lithium-storage performance, including ah igh reversible capacity (424.5 mA h À1 g À1 at 50 mA g À1 ), excellent stability( 0.016 %c apacityd ecay per cycle during 180 cycles), and remarkable rate capability (275.8 mA h À1 g À1 at 2000 mA g À1 ).Supporting information and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

New Amorphous Iron-Based Oxyfluorides as Cathode Materials for High-Capacity Lithium-Ion Batteries

“…New synthesis methods were developed to prepare fluorinated materials: they enlist either the heat treatment of FeSiF 6 ·6H 2 O to obtain the nonstoichiometric oxyfluoride FeO 0.7 F 1.3 , ,, the alcoholysis of FeOF from FeF 3 ·3H 2 O or FeF 2 ·4H 2 O to obtain the rutile form of FeOF, − or the high energy ball milling of LiF together with FeO to prepare a new cubic variety of FeOF . Another interesting alternative route is the reaction of high-voltage charged MnO with LiPF 6 electrolyte to generate a Mn–O–F phase with a highly disordered O-rich cubic-spinel-like core and a F-rich amorphous shell displaying great performances as cathode materials in LiBs. , More recently, Fan et al reported a Co 0.1 Fe 0.9 OF electrode, made from a concerted doping of cobalt and oxygen into iron fluoride, which shows a sustained reversible capacity of 350 mAh·g –1 at high rate, hence stressing further the importance of having the proper 3d-metal …”

FeOF/TiO2 Hetero-Nanostructures for High-Areal-Capacity Fluoride Cathodes

“…Electrochemical Performance. We first investigated the electrochemical properties of the FeOF@CNT and FeOF/ TiO 2 @CNT cathodes at a mass loading of 1.5 mg cm −2 , a common value in literatures (Figure 3), 9,17,20,28 for understanding their electrochemical properties. The mass is based on FeOF for FeOF@CNT and FeOF + TiO 2 for FeOF/TiO 2 @ CNT.…”

“…First, a 3D porous CNT sponge is used as the substrate to support FeOF nanoparticles with a typical size of 5–10 nm. This is so far the smallest primary FeOF nanoparticles reported, while others are typically >10 nm. ,− The electronically conductive CNTs provide fast channels for electron transport, and the open porous structure facilitates ion diffusion in the electrolyte. TiO 2 nanoparticles are then uniformly introduced into the FeOF@CNT hybrid structure using a simple solution process at room temperature, thus avoiding the reduction issue with a carbon coating.…”

Nanostructured Iron Fluoride Derived from Fe-Based Metal–Organic Framework for Lithium Ion Battery Cathodes

“…The small reversible redox peaks at 2.25 and 2.35 V in the curves may be verified as lithium intercalation/deintercalation peaks of FeOF owing to incomplete fluorination of the O−Fe-MOF. 58 For the S-FeF 3 • 0.33H 2 O, the oxidation peak is widened and shifted to a higher voltage, with the potentials at 2.97 and 3.45 V.…”