APS March Meeting 2016
Volume 61, Number 2
Monday–Friday, March 14–18, 2016;
Baltimore, Maryland
Session B33: Polymers in Batteries
11:15 AM–2:15 PM,
Monday, March 14, 2016
Room: 336
Sponsoring
Unit:
DPOLY
Chair: Brad Frieberg, NIST
Abstract ID: BAPS.2016.MAR.B33.4
Abstract: B33.00004 : NMR Investigations of Structure and Dynamics in Polymers for Energy Storage Applications*
11:51 AM–12:27 PM
Preview Abstract
Abstract
Author:
Steven Greenbaum
(Hunter College of the City University of New York)
Materials innovation is needed to realize major progress in energy storage
capacity for lithium batteries and capacitors. Polymers hold considerable
promise as ion conducting media in batteries and electrochemical capacitors
and as dielectrics in thin film capacitors.
Structural studies of materials utilized in lithium battery technology are
hampered by the lack of long-range order found in well-defined crystalline
phases. Powder x-ray diffraction yields structural parameters that have been
averaged over hundreds of lattice sites, and is unable to provide structural
information about amorphous phases. Our laboratory uses solid state nuclear
magnetic resonance (NMR) methods to investigate structural and chemical
aspects of lithium ion cathodes, anodes, electrolytes, interfaces and
interphases. NMR is element- (nuclear-) specific and sensitive to small
variations in the immediate environment of the ions being probed, for
example Li$^{\mathrm{+}}$, and in most cases is a reliably quantitative
spectroscopy in that the integrated intensity of a particular spectral
component is directly proportional to the number of nuclei in the
corresponding material phase. NMR is also a powerful tool for probing ionic
and molecular motion in lithium battery electrolytes with a dynamic range
spanning some ten orders of magnitude through spin-lattice relaxation and
self-diffusion measurements. Broadband relaxometry based on Fast Field
Cycling NMR (FFCNMR) methods can span three to four of these orders of
magnitude in a single set of measurements.
Results of several recent NMR investigations performed on our lab will be
presented. We explore the ion transport mechanism in polyether-based and
lithium polymer electrolytes and those based on other base polymers, in
particular, the extent to which ionic motion is coupled to polymer segmental
motion. Polycarbonates are being considered as a possible replacement for
polypropylene in high power thin film capacitors due to their favorable
dielectric properties. We investigate the effects of incorporation of two
types of additives in the polymer film on the ring-flip motions
corresponding to the $\gamma $ relaxation: (i) high dielectric constant
ceramic particles; (ii) polar organic diluent molecules, The low frequency
realm of broadband relaxometry allows meaningful comparison with dielectric
relaxation studies of these samples performed by collaborators.
*Work Supported in part by the U.S. Office of Naval Research
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2016.MAR.B33.4