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

Title: Structural Defects of Silver Hollandite, AgxMn8Oy, Nanorods: Dramatic Impact on Electrochemistry

Journal Article · · ACS Nano
 [1];  [2];  [1];  [3];  [3];  [3];  [1];  [3];  [4];  [3]
  1. Brookhaven National Lab. (BNL), Upton, NY (United States)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States); Southeast Univ., Nanjing (China)
  3. Stony Brook Univ., NY (United States)
  4. Stony Brook Univ., NY (United States); Brookhaven National Lab. (BNL), Upton, NY (United States)

Hollandites (OMS-2) are an enticing class of sorbents, catalysts, and energy storage materials with a tunnel structure permitting one-dimensional insertion and deinsertion of ions and small molecules along the c direction. A 7-fold increase in delivered capacity for Li/AgxMn8O16 electrochemical cells (160 versus 23 mAh/g) observed upon a seemingly small change in silver content (x ~1.1 (L-Ag-OMS-2) and 1.6 (H-Ag-OMS-2)) led us to characterize the structure and defects of the silver hollandite material. In this work, Ag hollandite nanorods are studied through the combined use of local (atomic imaging, electron diffraction, electron energy-loss spectroscopy) and bulk (synchrotron based X-ray diffraction, thermogravimetric analysis) techniques. Selected area diffraction and high resolution transmission electron microscopy show a structure consistent with that refined by XRD; however, the Ag occupancy varies significantly even within neighboring channels. Both local and bulk measurements indicate a greater quantity of oxygen vacancies in L-Ag-OMS-2, resulting in lower average Mn valence relative to H-Ag-OMS-2. Electron energy loss spectroscopy shows a lower Mn oxidation state on the surface relative to the interior of the nanorods, where the average Mn valence is approximately Mn3.7+ for H-Ag-OMS-2 and Mn3.5+ for L-Ag-OMS-2 nanorods, respectively. The higher delivered capacity of L-Ag-OMS-2 may be related to more oxygen vacancies compared to H-Ag-OMS-2. Thus, the oxygen vacancies and MnO6 octahedra distortion are assumed to open the MnO6 octahedra walls, facilitating Li diffusion in the ab plane. These results indicate crystallite size and surface defects are significant factors affecting battery performance.

Research Organization:
Energy Frontier Research Centers (EFRC) (United States). Center for Mesoscale Transport Properties (m2M); Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division
Grant/Contract Number:
SC0012673; SC0012704
OSTI ID:
1370520
Journal Information:
ACS Nano, Vol. 9, Issue 8; Related Information: m2M partners with Stony Brook University (lead); Brookhaven National Laboratory; Columbia University; Georgia Institute of Technology; Oak Ridge National Laboratory; Rensselaer Polytechnic Institute; University of California, Berkeley; University of North Carolina at Chapel Hill; ISSN 1936-0851
Publisher:
American Chemical Society (ACS)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 77 works
Citation information provided by
Web of Science

References (30)

Effects of Cu 2+ Ions on the Structure and Reactivity of Todorokite- and Cryptomelane-Type Manganese Oxide Octahedral Molecular Sieves journal July 1999
Selective exchange of divalent transition metal ions in cryptomelane-type manganic acid with tunnel structure journal March 1993
Synthesis and Characterization of Silver Hollandite and Its Application in Emission Control journal August 2005
Sorption Behavior of Radionuclides on Crystalline Synthetic Tunnel Manganese Oxides journal December 2000
Direct Sonochemical Synthesis of Manganese Octahedral Molecular Sieve (OMS-2) Nanomaterials Using Cosolvent Systems, Their Characterization, and Catalytic Applications journal February 2012
Microwave-Assisted Hydrothermal Synthesis of Cryptomelane-Type Octahedral Molecular Sieves (OMS-2) and Their Catalytic Studies journal June 2010
Synthetic Routes to Microporous Manganese Oxides journal October 1997
The structure of K 1.33 Mn 8 O 16 and cation ordering in hollandite-type structures journal April 1986
Structural, Magnetic and Electronic Transport Properties of Novel Hollandite-Type Molybdenum Oxide, Rb 1.5 Mo 8 O 16 journal January 2006
A Review of Porous Manganese Oxide Materials journal October 1998
Ag1.8Mn8O16: Square Planar Coordinated Ag⊕ Ions in the Channels of a Novel Hollandite Variant journal November 1984
Synthesis and Characterization of Ag−Hollandite Nanofibers and Its Catalytic Application in Ethanol Oxidation journal August 2007
Large-scale synthesis of Ag1.8Mn8O16 nanorods and their electrochemical lithium-storage properties journal January 2011
Synthesis and Electrochemistry of Silver Hollandite journal January 2010
Synthetic Control of Composition and Crystallite Size of Silver Hollandite, Ag x Mn 8 O 16 : Impact on Electrochemistry journal September 2012
The Electrochemistry of Silver Hollandite Nanorods, Ag x Mn 8 O 16 : Enhancement of Electrochemical Battery Performance via Dimensional and Compositional Control journal January 2013
Hollandites as a new class of multiferroics journal August 2014
Electrochemical performance and ex situ analysis of ZnMn2O4 nanowires as anode materials for lithium rechargeable batteries journal February 2011
Microstructural Features of α-MnO[sub 2] Electrodes for Lithium Batteries journal January 1998
Frame Stability of Tunnel-Structured Cryptomelane Nanofibers: The Role of Tunnel Cations journal July 2013
Extraction of EELS white-line intensities of manganese compounds: Methods, accuracy, and valence sensitivity journal March 2006
Alkali Metal Ions Insertion/Extraction Reactions with Hollandite-Type Manganese Oxide in the Aqueous Phase journal January 1995
ESCA and thermodynamic studies of alkali metal ion exchange reactions on an α-MnO2 phase with the tunnel structure journal January 2000
Large-Scale Synthesis of Silver Manganese Oxide Nanofibers and Their Oxygen Reduction Properties journal November 2013
White lines and d -electron occupancies for the 3 d and 4 d transition metals journal April 1993
Advanced Computing in Electron Microscopy book January 1998
Two-dimensional detector software: From real detector to idealised image or two-theta scan journal January 1996
GSAS-II : the genesis of a modern open-source all purpose crystallography software package journal March 2013
Unit-cell refinement from powder diffraction scans journal December 1981
R factors in Rietveld analysis: How good is good enough? journal March 2006

Cited By (11)

Suppressing Manganese Dissolution in Potassium Manganate with Rich Oxygen Defects Engaged High‐Energy‐Density and Durable Aqueous Zinc‐Ion Battery journal February 2019
Manganese-Oxide-Based Electrode Materials for Energy Storage Applications: How Close Are We to the Theoretical Capacitance? journal August 2018
Synthesis of Silver Hollandite Nanorectangular Cuboids as Negative Electrode Material for High-Performance Asymmetric Supercapacitors and Lithium-Ion Capacitors journal October 2018
Gas–solid interfacial modification of oxygen activity in layered oxide cathodes for lithium-ion batteries journal July 2016
Visualization of lithium-ion transport and phase evolution within and between manganese oxide nanorods journal May 2017
A-site compositional effects in Ga-doped hollandite materials of the form BaxCsyGa2x+yTi8−2x−yO16: implications for Cs immobilization in crystalline ceramic waste forms journal June 2016
Interlinked multiphase Fe-doped MnO 2 nanostructures: a novel design for enhanced pseudocapacitive performance journal January 2016
Charge localization and ordering in A 2 Mn 8 O 16 hollandite group oxides: Impact of density functional theory approaches journal December 2017
Interface reconstruction with emerging charge ordering in hexagonal manganite journal May 2018
Capacity Retention for (De)lithiation of Silver Containing α-MnO 2 : Impact of Structural Distortion and Transition Metal Dissolution journal January 2018
Synthesis and Characterization of 2 × 4 Tunnel Structured Manganese Dioxides as Cathodes in Rechargeable Li, Na, and Mg Batteries journal January 2019