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Multinuclear NMR Study of Lithiated Silver Vanadium Oxide

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Rechargeable Cars. The Challenge. To create secondary batteries that are the following: ... NMR Magnet. Pictures of the Hunter NMR Lab ... – PowerPoint PPT presentation

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Title: Multinuclear NMR Study of Lithiated Silver Vanadium Oxide


1
Multinuclear NMR Study of Lithiated Silver
Vanadium Oxide
  • By Christina Zayas, Aquinas High School
  • Mentors
  • Ms. Nicole Leifer, CUNY Doctoral Student
  • Dr. Steve Greenbaum, Professor of Physics at
    Hunter College

2
IntroductionGoal of Experiment
  • To test the hypothesis that the Ag ions are
    reduced during the beginning stages of lithiation
    before V4 at higher lithium content.
  • The ability to determine which undergoes
    reduction first will enable us to determine what
    actually happens at a microscopic level.
  • Ag0 is an excellent conductor. Therefore, the
    ability to reduce Ag 2 1 to Ag 0 first will
    allow increased electric conductivity, which
    would result in longer lasting primary and
    secondary batteries.

3
A Lithiated Silver Vanadium Oxide Model
LiAsF6
4
What is NMR Spectroscopy?
  • Nuclear Magnetic Resonance (NMR) is a phenomenon
    that occurs when the nuclei of certain atoms are
    immersed in a static magnetic field and exposed
    to a second magnetic field.
  • Spectroscopy is the study of the interaction of
    electromagnetic radiation with matter.

5
NMR Spectroscopy
  • NMR Spectroscopy is the use of the NMR phenomenon
    to study physical, chemical, and biological
    properties of matter.
  • Studies are done by analyzing spectrums that are
    produced through NMR.

6
NMR and Spin
  • NMR only happens with nuclei with spin.
  • Spin is a fundamental property of all unpaired
    electrons, protons, and neutrons.
  • In NMR, there is only a concern for the unpaired
    spin of the nuclei (no electrons)
  • NMR can only be performed on isotopes whose
    natural abundance is high enough to be detected.

7
What is Spin?
  • Protons will have a spin that is similar to a
    magnetic moment vector, causing the proton to
    behave like a tiny magnet with a north and south
    pole.
  • When the proton is placed in an external magnetic
    field, the spin vector of the particle aligns
    itself with the external field, just like a
    magnet would.

8
How can NMR help to create better batteries?
  • NMR spectrum is sensitive to a number of physical
    parameters that are directly related to the
    efficacy of the working cell.
  • Li-ion mobility, electronic conductivity, and
    changes in the valence or electronic structures
    of the cations that are involved in the redox
    processes
  • It is element-specific and may be use to directly
    examine the species that are involved in the
    working battery.

9
Why do we need better batteries?
  • To power things like

Pacemakers
Hearing Aids
Rechargeable Cars
10
The Challenge
  • To create secondary batteries that are the
    following
  • Higher in energy
  • Have a longer life span
  • Are convenient to use
  • Are durable

11
Secondary Batteries
Nickel Cadmium Battery
Lead Acid Battery
Lithium Battery
12
Experiment
  • This graph indicates that vanadium has an
    oxidation state of 4 at this level of lithium.
  • It is paramagnetic and parabroading at this
    level.
  • The electron configuration is 1s22s22p63s23p64s1,
    which means that it has only one electron and it
    is paramagnetic.

13
Experiment -continued
  • In Figures 2 and 3, the lithium levels are
    decreased and as a result V4 does not occur.
  • It is not paramagnetic.

14
Conclusion
  • It has been concluded so far that lithiated
    silver vanadium oxide could be useful to create
    better secondary batteries.
  • Further research is needed to determine its
    usefulness under all conditions.
  • This has been a delay in our lab because some of
    the machines were broken.

NMR Magnet
15
Pictures of the Hunter NMR Lab
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