skip to main content

DOE PAGESDOE PAGES

Title: Rate Dependent Multi-Mechanism Discharge of Ag 0.50VOP 4·1.8H 2O: Insights from In Situ Energy Dispersive X-ray Diffraction

Ag 0.50VOPO 4·1.8H 2O (silver vanadium phosphate, SVOP) demonstrates a counterintuitive higher initial loaded voltage under higher discharge current. Energy dispersive X-ray diffraction (EDXRD) from synchrotron radiation was used to create tomographic profiles of cathodes at various depths of discharge for two discharge rates. SVOP displays two reduction mechanisms, reduction of a vanadium center accompanied by lithiation of the structure, or reduction-displacement of a silver cation to form silver metal. In-situ EDXRD provides the opportunity to observe spatially resolved changes to the parent SVOP crystal and formation of Ag 0 during reduction. At a C/170 discharge rate V 5+ reduction is the preferred initial reaction resulting in higher initial loaded voltage. At a discharge rate of C/400 reduction of Ag + with formation of conductive Ag 0 occurs earlier during discharge. Discharge rate also affects the spatial location of reduction products. The faster discharge rate initiates reduction close to the current collector with non-uniform distribution of silver metal resulting in isolated cathode areas. The slower rate develops a more homogenous distribution of reduced SVOP and silver metal. This study illuminates the roles of electronic and ionic conductivity limitations within a cathode at the mesoscale and how they impact the coursemore » of reduction processes and loaded voltage.« less
Authors:
 [1] ;  [2] ;  [2] ;  [3] ;  [3] ;  [4] ;  [5] ;  [5]
  1. Stony Brook Univ., NY (United States). Department of Materials Science and Engineering
  2. Brookhaven National Lab. (BNL), Upton, NY (United States). Energy Sciences Directorate
  3. Stony Brook Univ., NY (United States). Dept. of Chemistry
  4. 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;
  5. Stony Brook Univ., NY (United States). Department of Materials Science and Engineering and Department of Chemistry
Publication Date:
Report Number(s):
BNL-113937-2017-JA
Journal ID: ISSN 0013-4651
Grant/Contract Number:
SC0012704
Type:
Accepted Manuscript
Journal Name:
Journal of the Electrochemical Society
Additional Journal Information:
Journal Volume: 164; Journal Issue: 1; Journal ID: ISSN 0013-4651
Publisher:
The Electrochemical Society
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:
25 ENERGY STORAGE; 36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; cathode material; energy dispersive x-ray diffraction; lithium battery; silver vanadium phosphorous oxide
OSTI Identifier:
1376103