Poster Presentation 12
An Electrochemical Approach to Measuring Oxidative Stability of
Solid Polymer Electrolytes for Lithium Batteries
Brandon McGill, Daniel T. Hallinan Jr., Alexander Rausch
a
Florida State University — Aero-propulsion, Mechatronics & Energy Center — 2003 Levy Avenue, Tallahassee, FL 32310, USA
Florida A&M University-Florida State University College of Engineering, Department of Chemical and Biomedical Engineering,
2525 Pottsdamer Street, Tallahassee, FL 32310, USA
b
Abstract
Polymer electrolytes are an interesting class of electrolytes that hold promise for safer, flexible, high-energy
batteries. Their unique properties stem from being a solid-state ion conductor. This benefit is a challenge for
electrochemical investigations, since most electrochemical experiments have been designed for liquid
electrolyte. In order to quantitatively evaluate polymer electrolyte stability, an electrochemical approach
especially designed for solid electrolytes is presented. This approach uses a set of linear sweep voltammograms
from different, large overpotentials to open circuit voltage, which the authors term variable reverse linear sweep
voltammetry. By allowing the cell to relax between each polarization, the first data points of each
voltammogram are not mass transfer limited. This yields current versus overpotential data that can be analyzed
with a kinetic model, such as the Butler-Volmer model. Oxidative stability of poly(ethylene oxide) and
polystyrene-b-poly(ethylene oxide) with lithium bis-trifluoromethanesulfonimide salt has been investigated on
several electrode materials. The block copolymer electrolyte has been found to be quite stable to
electrochemical oxidation, up to 5 V at 40 °C. The degradation reaction has been found to be slow with large
thermal activation energy.
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