Miscible Polymer Blend Electrolytes
ORAL
Abstract
This study shows that it is possible to obtain homogeneous mixtures of two chemically distinct polymers with a lithium salt for electrolytic applications. This approach is motivated by the success of using mixtures of organic solvents in modern lithium-ion batteries. The properties of mixtures of a polyether, poly(ethylene oxide) (PEO), a poly(ether-acetal), poly(1,3,6-trioxocane) (P(2EO-MO)), and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt were studied using small angle neutron scattering and electrochemical characterization in symmetric cells. The SANS data are used to determine the miscibility window and quantify the effect of added salt on the thermodynamic interactions between the polymers. In the absence of salt, PEO/P(2EO-MO) blends are homogeneous and characterized by attractive interactions, i.e., a negative Flory-Huggins interaction parameter. The addition of small amounts of salt results in a positive effective Flory-Huggins interaction parameter, and macrophase separation. Surprisingly, miscible blends and negative interaction parameters are obtained when salt concentration is increased beyond a critical value. A brief summary of electrochemical properties of the miscible polymer blend electrolytes will also be presented.
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Presenters
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Nitash Balsara
University of California, Berkeley, Chemical and Biomolecular Engineering, University of California, Berkeley, College of Chemistry, University of California, Berkeley
Authors
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Nitash Balsara
University of California, Berkeley, Chemical and Biomolecular Engineering, University of California, Berkeley, College of Chemistry, University of California, Berkeley