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Title: Electrode Reaction Mechanism of Ag 2VO 2PO 4 Cathode

In this study, the high capacity of primary lithium-ion cathode Ag 2VO 2PO 4 is facilitated by both displacement and insertion reaction mechanisms. Whether the Ag extrusion (specifically, Ag reduction with Ag metal displaced from the host crystal) and V reduction are sequential or concurrent remains unclear. A microscopic description of the reaction mechanism is required for developing design rules for new multimechanism cathodes, combining both displacement and insertion reactions. However, the amorphization of Ag 2VO 2PO 4 during lithiation makes the investigation of the electrode reaction mechanism difficult with conventional characterization tools. For addressing this issue, a combination of local probes of pair-distribution function and X-ray spectroscopy were used to obtain a description of the discharge reaction. We determine that the initial reaction is dominated by silver extrusion with vanadium playing a supporting role. In addition, once sufficient Ag has been displaced, the residual Ag + in the host can no longer stabilize the host structure and V–O environment (i.e., onset of amorphization). After amorphization, silver extrusion continues but the vanadium reduction dominates the reaction. As a result, the crossover from primarily silver reduction displacement to vanadium reduction is facilitated by the amorphization that makes vanadium reduction increasingly moremore » favorable.« less
Authors:
 [1] ;  [2] ;  [3] ;  [3] ;  [4] ;  [4] ;  [5] ;  [6] ;  [7] ;  [8] ;  [8] ;  [9] ;  [2] ;  [3]
  1. The State University of New York at Binghamton, NY (United States). Institute for Materials Research; Binghamton Univ., NY (United States). Department of Physics, Applied Physics and Astronomy
  2. The State University of New York at Buffalo, NY (United States). Department of Physics
  3. Binghamton Univ., NY (United States). Department of Physics, Applied Physics and Astronomy
  4. Stony Brook Univ., NY (United States). Department of Materials Science and Engineering
  5. Brookhaven National Lab. (BNL), Upton, NY (United States). Energy Sciences Directorate
  6. The State University of New York Polytechnic Institute, Albany, NY (United States). Colleges of Nanoscale Science and Engineering
  7. The State University of New York at Binghamton, NY (United States). Institute for Materials Research and Department of Chemistry
  8. Stony Brook Univ., NY (United States). Department of Materials Science and Engineering and Department of Chemistry
  9. Stony Brook Univ., NY (United States). Department of Materials Science and Engineering and Department of Chemistry ; Brookhaven National Lab. (BNL), Upton, NY (United States). Energy Sciences Directorate
Publication Date:
Report Number(s):
BNL-112481-2016-JA
Journal ID: ISSN 0897-4756
Grant/Contract Number:
SC0012704; AC02-06CH11357; AC02-05CH11231
Type:
Accepted Manuscript
Journal Name:
Chemistry of Materials
Additional Journal Information:
Journal Volume: 28; Journal Issue: 10; Journal ID: ISSN 0897-4756
Publisher:
American Chemical Society (ACS)
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 25 ENERGY STORAGE; Electrode reaction; Cathode; Ag; reaction mechanism; amorphization
OSTI Identifier:
1336084