Lithium ion batteries and hydrogen fuel cells represent two very important and still emerging energy technologies for applications in transportation and aerospace. A key component in both of these devices is the electrolyte membrane which transports the

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High Pressure NMR Studies of Lithium-Ion
Batteries and Fuel Cell Membranes
Christian E. Mejia (HSS), Richner Erisnor (HST),
Steve Greenbaum (PI), Jaime Farrington (GS),
Christoph Weise (PD) Hunter College Dept. of
Physics and Astronomy
INTRODUCTION
SAMPLES AND PREPARATION
RESULTS
Lithium ion batteries and hydrogen fuel cells
represent two very important and still emerging
energy technologies for applications in
transportation and aerospace. A key component in
both of these devices is the electrolyte membrane
which transports the ions between the electrodes.
Ionic liquids are a new class of materials with
desirable properties such as high ionic
conductivity, chemical and thermal stability. New
membranes incorporating ionic liquids into a
polymer matrix are now being evaluated for
battery and fuel cell applications.

• 1 Butyl 1 ethylpyrrolidinium
  bis(trifluoromethanesulfonyl)imide ionic
  liquid (Py24TFSI)

TFSI (Anion) C2F6NO4S2
Py (Cation) C10H22N

• 0.2M solution of Py24TFSI and LiTFSI
• LiTFSI(Py24TFSI) 0.2m solution in a PVdF
  membrane (Py24TFSI M80)

Lithium-Ion Battery
These samples were prepared in the University of
Rome, by Dr. Alessandra DEpifanio
NMR EXPERIMENTAL SETUP
PEM - FUEL CELL
Above is shown the diffusion data of the
LiTFSI(Py24TFSI) at 30o and 50 o C at the maximum
pressure of the system, 2500 atm
CONCLUSION
Preliminary data are presented for both the ionic
liquid and its corresponding membrane at two
different temperatures, 30o and 55oC, at the
maximum system pressure of 2,500 atm. (0.25 GPa).
The cation diffusion coefficients extracted from
the raw spin-echo decay data are listed on the
plots. As expected, D is higher in the liquid
than in the membrane, and as is also expected for
both free liquid and membrane, raising the
temperature at fixed pressure also increases D.
However, it is also seen that the percentage
increase in D is much larger in the liquid than
in the membrane, thus implying that there is
significant restriction of cation motion by
interaction with the host polymer.
Nuclear magnetic resonance (NMR) is one of the
premier methods to investigate ionic mobility in
media such as liquids and membranes. One
parameter that can be directly obtained from the
NMR measurements is the self-diffusion
coefficient, D. One often measures D as a
function of temperature to learn more about the
material. This laboratory has developed the means
to measure D as a function of pressure. Having
the capability to adjust two independent
thermodynamic variables can yield much insight
into the mechanisms of ionic and molecular
motion.
Sponsors National Aeronautics and Space
Administration (NASA) NASA Goddard Space Flight
Center (GSFC) NASA Goddard Institute for Space
Studies (GISS) NASA New York City Research
Initiative (NYCRI)