Retracted Article: Mesoporous amorphous FeOF nanococoons for high-rate and long-life rechargeable sodium-ion batteries

Abstract

A novel solution plasma processing approach was developed to synthesize mesoporous amorphous FeOF nanococoons on a large scale via using NaF and FeCl3•xH2O as the precursors, and CO2 released from the hydrolysis of urea as the growth director. The obtained mesoporous amorphous FeOF nanococoons deliver a reversible capacity of 238.9 mAhg -1 at a current rate of 1 Ag -1 and show almost no degradation, even after 3000 cycles by adopting the optimized 1.0 M sodium trifluoromethanesulfonate (NaTFSA) in triglyme (TGM) as the electrolyte and applying the cut-off voltage to 1.3 V. Furthermore, the nanococoons exhibit a capacity of 190.4 mAhg −1 at an ultrahigh current density of 20 Ag −1 because of the coexisting pseudocapacitance-type reaction. Meanwhile, the attempt for commercial 18650 batteries exhibited a stable discharge capacity of 4897 mAh at 4 A for 300 cycles, which allows for consideration for this type of room-temperature battery in commercial utilization. The superior electrochemical performance of the mesoporous amorphous FeOF nanococoons is because of the collaboration of optimized electrolyte, controlling the terminate voltage to 1.3V, and its particular nanostructure, which significantly improve the ionic and electronic transport and intercalation kinetics of Na ions.

Ultrasmall Iron Fluoride Nanoparticles Embedded in Graphitized Porous Carbon Derived from Fe‐Based Metal Organic Frameworks as High‐Performance Cathode Materials for Li Batteries

“…The small reversible redox peaks at 2.2 V and 2.4 V in the CV profiles can be confirmed as a lithium intercalation/ deintercalation peaks of FeOF derived from incomplete fluorination of Fe 3 O 4 for which is tightly covered by graphitized carbon. [35,36] Since the content may be too small and coated by the carbon layer, the XRD and XPS test doesn't detect the presence of FeOF.…”

Recent Progress in Iron‐Based Electrode Materials for Grid‐Scale Sodium‐Ion Batteries

“…The obtained FeO 0.7 F 1.3 /C electrode exhibited a high initial discharge capacity of 496 mAh g −1 in a sodium cell at 50 °C, and the reaction mechanism studies of FeO 0.7 F 1.3 /C with sodium showed a hybridized mechanism of both the intercalation and conversion reactions . Afterwards, Tong and co‐workers reported mesoporous amorphous FeOF nanococoons (Figure b,d), which exhibited a high reversible capacity of ≈240 mAh g −1 with both a high rate capability (190 mAh g −1 at 20 mA g −1 ) and a long cycle life (3000 cycles) …”

“…Copyright 2011, Elsevier. b,d) Reproduced with permission . Copyright 2015, Royal Society of Chemistry.…”

From Crystalline to Amorphous: An Effective Avenue to Engineer High‐Performance Electrode Materials for Sodium‐Ion Batteries

“…E) Electrochemical characterization of the mesoporous amorphous FeOF nanococoons: (a) galvanostatic discharging/charging profiles performed at a current density of 0.2 A g −1 ; and (b) rate capability. Reproduced with permission . Copyright 2015, Royal Society of Chemistry.…”

“…However, it should be noted that the existing synthesis strategy suffers from several limitations, such as high reaction temperature and high pressure, usage of corrosive hydrofluoric acid, or toxic F 2 . Fu et al synthesize amorphous FeOF with mesoporous structure via a solution plasma processing method . The as‐prepared material provides fruitful open pores beneficial to the electrolyte penetration, increase in the conductivity and reduce in the diffusion pathway, leading to a better electrochemical performance than the crystalline FeOF (Figure E).…”