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Title: Li/Ag 2VO 2PO 4 batteries: the roles of composite electrode constituents on electrochemistry

In this study, we utilize silver vanadium phosphorous oxide, Ag 2VO 2PO 4, as a model system to systematically study the impact of the constituents of a composite electrode, including polymeric and conductive additives, on electrochemistry. Notably, although highly resistive, this bimetallic cathode can be discharged as a pure electroactive material in the absence of a conductive additive as it generates an in situ conductive matrix via a reduction displacement reaction resulting in the formation of silver metal nanoparticles. Also, three different electrode compositions were investigated: Ag 2VO 2PO 4 only, Ag 2VO 2PO 44 with binder, and Ag 2VO 2PO 4 with binder and carbon. Constant current discharge, pulse testing and impedance spectroscopy measurements were used to characterize the electrochemical properties of the electrodes as a function of depth of discharge. In situ EDXRD was used to spatially resolve the discharge progression within the cathode by following the formation of Ag 0. Ex situ XRD and EXAFS modeling were used to quantify the amount of Ag 0 formed. Results indicate that the metal center reduced (V 5+ or Ag +) was highly dependent on composite composition (presence of PTFE, carbon), depth of discharge (Ag 0 nanoparticle formation), and spatialmore » location within the cathode. The addition of a binder was found to increase cell polarization, and the percolation network provided by the carbon in the presence of PTFE was further increased with reduction and formation of Ag 0. Lastly, this study provides insight into the factors controlling the electrochemistry of resistive active materials in composite electrodes.« less
Authors:
 [1] ;  [2] ;  [1] ;  [2] ;  [3] ;  [3] ;  [4]
  1. Brookhaven National Lab. (BNL), Upton, NY (United States)
  2. Stony Brook Univ., NY (United States). Dept. of Chemistry
  3. Stony Brook Univ., NY (United States). Dept. of Chemistry and Department of Materials Science and Engineering
  4. Brookhaven National Lab. (BNL), Upton, NY (United States); Stony Brook Univ., NY (United States). Dept. of Chemistry and Department of Materials Science and Engineering
Publication Date:
Report Number(s):
BNL-113549-2017-JA
Journal ID: ISSN 2046-2069; RSCACL
Grant/Contract Number:
SC00112704; SC0012673; AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
RSC Advances
Additional Journal Information:
Journal Volume: 6; Journal Issue: 108; Journal ID: ISSN 2046-2069
Publisher:
Royal Society of Chemistry
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; batteries; composite; electrode; electrochemistry
OSTI Identifier:
1347289