skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Controlled Formation of Mixed Nanoscale Domains of High Capacity Fe2O3–FeF3 Conversion Compounds by Direct Fluorination

Journal Article · · ACS Nano
 [1];  [1];  [2];  [1];  [3];  [4]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division
  2. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemistry
  3. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemistry; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Univ. of Tennessee, Knoxville, TN (United States). Bredesen Centre for Interdisciplinary Science and Graduate Education. Dept. of Chemical and Biomolecular Engineering
+ Show Author Affiliations

In this paper, we report a direct fluorination method under fluorine gas atmosphere using a fluidized bed reactor for converting nanophase iron oxide (n-Fe2O3) to an electrochemically stable and higher energy density iron oxyfluoride/fluoride phase. Interestingly, no noticeable bulk iron oxyfluoride phase (FeOF) phase was observed even at fluorination temperature close to 300 °C. Instead, at fluorination temperatures below 250 °C, scanning transmission electron microscopy coupled with electron energy loss spectroscopy (STEM-EELS) and X-ray photoelectron spectroscopy (XPS) analysis showed surface fluorination with nominal composition, Fe2O3-xF2x (x < 1). At fluorination temperatures of 275 °C, STEM-EELS results showed porous interconnected nanodomains of FeF3 and Fe2O3 coexisting within the same particle, and overall the particles become less dense after fluorination. We performed potentiometric intermittent titration and electrochemical impedance spectroscopy studies to understand the lithium diffusion (or apparent diffusion) in both the oxyfluoride and mixed phase FeF3 + Fe2O3 composition, and correlate the results to their electrochemical performance. Finally and further, we analyze from a thermodynamical perspective, the observed formation of the majority fluoride phase (77% FeF3) and the absence of the expected oxyfluoride phase based on the relative formation energies of oxide, fluoride, and oxyfluorides.

Research Organization:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
Grant/Contract Number:
AC05-00OR22725
OSTI ID:
1286723
Journal Information:
ACS Nano, Vol. 9, Issue 3; ISSN 1936-0851
Publisher:
American Chemical Society (ACS)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 44 works
Citation information provided by
Web of Science

References (39)

Beyond Intercalation-Based Li-Ion Batteries: The State of the Art and Challenges of Electrode Materials Reacting Through Conversion Reactions journal August 2010
Direct Observation of Inhomogeneous Solid Electrolyte Interphase on MnO Anode with Atomic Force Microscopy and Spectroscopy journal January 2012
Nanostructured Fe3O4/SWNT Electrode: Binder-Free and High-Rate Li-Ion Anode journal May 2010
A preliminary investigation of the electrochemical performance of α-Fe2O3 and Fe3O4 cathodes in high-temperature cells journal May 1981
Formation of Fe 2 O 3 Microboxes with Hierarchical Shell Structures from Metal–Organic Frameworks and Their Lithium Storage Properties journal October 2012
?-Fe2O3 Nanotubes in Gas Sensor and Lithium-Ion Battery Applications journal March 2005
Hollow Iron Oxide Nanoparticles for Application in Lithium Ion Batteries journal April 2012
Facile Solution Synthesis of α-FeF 3 ·3H 2 O Nanowires and Their Conversion to α-Fe 2 O 3 Nanowires for Photoelectrochemical Application journal January 2012
Mesoporous Co 3 O 4 Nanowire Arrays for Lithium Ion Batteries with High Capacity and Rate Capability journal January 2008
Interface electrochemistry in conversion materials for Li-ion batteries journal January 2011
Conversion mechanism of nickel fluoride and NiO-doped nickel fluoride in Li ion batteries journal January 2012
Investigation of the Conversion Reaction Mechanisms for Binary Copper(II) Compounds by Solid-State NMR Spectroscopy and X-ray Diffraction journal July 2009
Metal hydrides for lithium-ion batteries journal October 2008
High-Capacity Lithium-Ion Battery Conversion Cathodes Based on Iron Fluoride Nanowires and Insights into the Conversion Mechanism journal October 2012
Carbon Metal Fluoride Nanocomposites: High-Capacity Reversible Metal Fluoride Conversion Materials as Rechargeable Positive Electrodes for Li Batteries journal January 2003
Hydrothermal synthesis and electrochemical properties of alpha-manganese sulfide submicrocrystals as an attractive electrode material for lithium-ion batteries journal September 2008
Transition-metal chlorides as conversion cathode materials for Li-ion batteries journal April 2012
Assembling carbon-coated α-Fe 2 O 3 hollow nanohorns on the CNT backbone for superior lithium storage capability journal January 2012
α-Fe2O3 Nanoflakes as an Anode Material for Li-Ion Batteries journal October 2007
Spindle-like Mesoporous α-Fe 2 O 3 Anode Material Prepared from MOF Template for High-Rate Lithium Batteries journal January 2012
Low temperature plasma synthesis of mesoporous Fe3O4 nanorods grafted on reduced graphene oxide for high performance lithium storage journal January 2014
Carbon-Metal Fluoride Nanocomposites: Structure and Electrochemistry of FeF3 : C journal January 2003
Li-Storage via Heterogeneous Reaction in Selected Binary Metal Fluorides and Oxides journal January 2004
Structure and Electrochemistry of Carbon-Metal Fluoride Nanocomposites Fabricated by Solid-State Redox Conversion Reaction journal January 2005
Fluoride based electrode materials for advanced energy storage devices journal April 2007
Iron Oxyfluorides as High Capacity Cathode Materials for Lithium Batteries journal January 2009
First-principles study of iron oxyfluorides and lithiation of FeOF journal March 2013
An Electron Diffraction and Crystal Chemical Investigation of Oxygen/Fluorine Ordering in Rutile-Type Iron Oxyfluoride, FeOF journal December 2000
Formation of Iron Oxyfluoride Phase on the Surface of Nano-Fe 3 O 4 Conversion Compound for Electrochemical Energy Storage journal October 2013
X-ray photoelectron study of the valence state of iron in iron-containing single-crystal (BiFeO3, PbFe1/2Nb1/2O3), and ceramic (BaFe1/2Nb1/2O3) multiferroics journal February 2011
Analysis of XPS spectra of Fe2+ and Fe3+ ions in oxide materials journal February 2008
The Dirac Vector Model in Complex Spectra journal March 1934
Synthesis and characterization of in situ Fe2O3-coated FeF3 cathode materials for rechargeable lithium batteries journal January 2012
Structural characterization of the lithiated iron oxides LixFe3O4 and LixFe2O3 (0<x<2) journal June 1982
Iron Oxide Nanosheets and Nanoparticles Synthesized by a Facile Single-Step Coprecipitation Method for Lithium-Ion Batteries journal January 2011
Transport, Phase Reactions, and Hysteresis of Iron Fluoride and Oxyfluoride Conversion Electrode Materials for Lithium Batteries journal April 2014
Low-Temperature Fluorination of Soft-Templated Mesoporous Carbons for a High-Power Lithium/Carbon Fluoride Battery journal October 2011
EXPGUI , a graphical user interface for GSAS journal April 2001
Dedicated STEM for 200 to 40 keV operation journal June 2011

Cited By (13)

Fluorination of MXene by Elemental F 2 as Electrode Material for Lithium‐Ion Batteries journal March 2019
Bio‐Inspired Synthesis of Hematite Mesocrystals by Using Xonotlite Nanowires as Growth Modifiers and Their Improved Oxygen Evolution Activity journal July 2019
In situ surface protection for enhancing stability and performance of conversion-type cathodes journal January 2017
Fluoride doped γ-Fe 2 O 3 nanoparticles with increased MRI relaxivity journal January 2018
Improved Performance in FeF 2 Conversion Cathodes through Use of a Conductive 3D Scaffold and Al 2 O 3 ALD Coating journal July 2017
Electrochemically driven conversion reaction in fluoride electrodes for energy storage devices journal April 2018
Toward Low-Cost, High-Energy Density, and High-Power Density Lithium-Ion Batteries journal June 2017
FeO x @carbon yolk/shell nanowires with tailored void spaces as stable and high-capacity anodes for lithium ion batteries journal January 2016
3D Honeycomb Architecture Enables a High‐Rate and Long‐Life Iron (III) Fluoride–Lithium Battery journal September 2019
Li-Rich Li[Li 1/6 Fe 1/6 Ni 1/6 Mn 1/2 ]O 2 (LFNMO) Cathodes: Atomic Scale Insight on the Mechanisms of Cycling Decay and of the Improvement due to Cobalt Phosphate Surface Modification journal September 2018
Defect-enriched iron fluoride-oxide nanoporous thin films bifunctional catalyst for water splitting journal May 2018
Fluorination of MXene by Elemental F 2 as Electrode Material for Lithium‐Ion Batteries journal April 2019
Fluorination of MXene by Elemental F 2 as Electrode Material for Lithium‐Ion Batteries journal March 2019

Similar Records

The preparation and characterization of iron fluorides polymorphs FeF{sub 3}·0.33H{sub 2}O and β-FeF{sub 3}∙3H{sub 2}O as cathode materials for lithium-ion batteries
Journal Article · Wed Apr 15 00:00:00 EDT 2015 · Materials Research Bulletin · OSTI ID:1286723
+8 more
Improved Performance in FeF2 Conversion Cathodes through Use of a Conductive 3D Scaffold and Al2O3 ALD Coating
Journal Article · Mon Jul 24 00:00:00 EDT 2017 · Advanced Functional Materials · OSTI ID:1286723
+3 more
Anionic ordering and thermal properties of FeF3·3H2O
Journal Article · Thu Sep 17 00:00:00 EDT 2015 · Inorganic Chemistry · OSTI ID:1286723
+5 more

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
conversion electrode
fluoride
fluorination
nano-Fe2O3