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Title: Microwave-Assisted Synthesis of Silver Vanadium Phosphorus Oxide, Ag 2VO 2PO 4 : Crystallite Size Control and Impact on Electrochemistry

We study silver vanadium phosphorus oxide, Ag 2VO 2PO 4, that is a promising cathode material for Li batteries due in part to its large capacity and high current capability. Herein, a new synthesis of Ag 2VO 2PO 4 based on microwave heating is presented, where the reaction time is reduced by approximately 100× relative to other reported methods, and the crystallite size is controlled via synthesis temperature, showing a linear correlation of crystallite size with temperature. Notably, under galvanostatic reduction, the Ag 2VO 2PO 4 sample with the smallest crystallite size delivers the highest capacity and shows the highest loaded voltage. Further, pulse discharge tests show a significant resistance decrease during the initial discharge coincident with the formation of Ag metal. Thus, the magnitude of the resistance decrease observed during pulse tests depends on the Ag 2VO 2PO 4 crystallite size, with the largest resistance decrease observed for the smallest crystallite size. Additional electrochemical measurements indicate a quasi-reversible redox reaction involving Li + insertion/deinsertion, with capacity fade due to structural changes associated with the discharge/charge process. In summary, this work demonstrates a faster synthetic approach for bimetallic polyanionic materials which also provides the opportunity for tuning of electrochemical propertiesmore » through control of material physical properties such as crystallite size.« less
Authors:
 [1] ;  [2] ;  [2] ;  [2]
  1. Stony Brook Univ., NY (United States). Department of Chemistry
  2. Stony Brook Univ., NY (United States). Department of Chemistry and Department of Materials Science and Engineering
Publication Date:
Report Number(s):
BNL-112457-2016-JA
Journal ID: ISSN 0897-4756
Grant/Contract Number:
SC0012704; SC0012673
Type:
Accepted Manuscript
Journal Name:
Chemistry of Materials
Additional Journal Information:
Journal Volume: 28; Journal Issue: 7; 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:
25 ENERGY STORAGE; 36 MATERIALS SCIENCE
OSTI Identifier:
1336075