skip to main content
DOE PAGES 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

Abstract

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 tomore » 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.« less

Authors:
 [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)
Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC) (United States). Center for Mesoscale Transport Properties (m2M); Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division
OSTI Identifier:
1370520
Grant/Contract Number:  
SC0012673; SC0012704
Resource Type:
Accepted Manuscript
Journal Name:
ACS Nano
Additional Journal Information:
Journal Volume: 9; Journal 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; Journal ID: ISSN 1936-0851
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
25 ENERGY STORAGE; silver hollandite; octahedral molecular sieve; oxygen defects; transmission electron microscopy; electron energy loss spectroscopy; lithium battery

Citation Formats

Wu, Lijun, Xu, Feng, Zhu, Yimei, Brady, Alexander B., Huang, Jianping, Durham, Jessica L., Dooryhee, Eric, Marschilok, Amy C., Takeuchi, Esther S., and Takeuchi, Kenneth J. Structural Defects of Silver Hollandite, AgxMn8Oy, Nanorods: Dramatic Impact on Electrochemistry. United States: N. p., 2015. Web. doi:10.1021/acsnano.5b03274.
Wu, Lijun, Xu, Feng, Zhu, Yimei, Brady, Alexander B., Huang, Jianping, Durham, Jessica L., Dooryhee, Eric, Marschilok, Amy C., Takeuchi, Esther S., & Takeuchi, Kenneth J. Structural Defects of Silver Hollandite, AgxMn8Oy, Nanorods: Dramatic Impact on Electrochemistry. United States. doi:10.1021/acsnano.5b03274.
Wu, Lijun, Xu, Feng, Zhu, Yimei, Brady, Alexander B., Huang, Jianping, Durham, Jessica L., Dooryhee, Eric, Marschilok, Amy C., Takeuchi, Esther S., and Takeuchi, Kenneth J. Thu . "Structural Defects of Silver Hollandite, AgxMn8Oy, Nanorods: Dramatic Impact on Electrochemistry". United States. doi:10.1021/acsnano.5b03274. https://www.osti.gov/servlets/purl/1370520.
@article{osti_1370520,
title = {Structural Defects of Silver Hollandite, AgxMn8Oy, Nanorods: Dramatic Impact on Electrochemistry},
author = {Wu, Lijun and Xu, Feng and Zhu, Yimei and Brady, Alexander B. and Huang, Jianping and Durham, Jessica L. and Dooryhee, Eric and Marschilok, Amy C. and Takeuchi, Esther S. and Takeuchi, Kenneth J.},
abstractNote = {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.},
doi = {10.1021/acsnano.5b03274},
journal = {ACS Nano},
number = 8,
volume = 9,
place = {United States},
year = {2015},
month = {7}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 30 works
Citation information provided by
Web of Science

Save / Share: