Microwave-Assisted Synthesis of Silver Vanadium Phosphorus Oxide, Ag₂VO₂PO₄ : Crystallite Size Control and Impact on Electrochemistry

Journal Article · Mon Mar 07 00:00:00 EST 2016 · Chemistry of Materials

DOI:https://doi.org/10.1021/acs.chemmater.6b00124· OSTI ID:1336075

Huang, Jianping ^[1]; Marschilok, Amy C. ^[2]; Takeuchi, Esther S. ^[2]; Takeuchi, Kenneth J. ^[2]

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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

We study silver vanadium phosphorus oxide, Ag₂VO₂PO₄, 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 Ag₂VO₂PO₄ 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 Ag₂VO₂PO₄ 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 Ag₂VO₂PO₄ 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 properties through control of material physical properties such as crystallite size.

• Research Organization: Brookhaven National Lab. (BNL), Upton, NY (United States); Energy Frontier Research Centers (EFRC) (United States). Center for Mesoscale Transport Properties (m2M)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: SC0012704; SC0012673
• OSTI ID: 1336075
• Report Number(s): BNL-112457-2016-JA
• Journal Information: Chemistry of Materials, Vol. 28, Issue 7; ISSN 0897-4756
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: English

Related Subjects

25 ENERGY STORAGE
36 MATERIALS SCIENCE