NEW MATERIALS DERIVED FROM POLY(4-HYDROXYSTYRENE) AS LITHIUM BATTERY CELL COMPONENTS

Abstract

A new class of polyethers has been prepared by the Mitsunobu coupling of poly(4-vinyl phenol), P4VP, with low molecular weight poly(ethylene glycol)methyl ether. These comb-like polymers, having ca. 20–30% residual phenols, were characterized by IR, DSC, and TGA. Results of thermal analysis on the polymers suggest thermal stability to at least 300°C and a glass transition temperature in the range −30 to −40°C. Complexes with LiPF₆ gave conductivities of ca. 1 × 10⁻⁵ S/cm at room temperature. The polymers were blended with plasticized poly(vinylidene fluoride) (PVDF) to prepare porous films and subsequently infiltrated with lithium salts and ethylene and ethyl methyl carbonate. Ionic conductivities of these hybrid films were measured from −20°C to 40°C. Conductivities as high as 2.4 × 10⁻³ S/cm are observed at room temperature. The electrochemical stability of hybrid materials was studied by cyclic voltammetry.

ACKNOWLEDGMENT

This work was supported by a U.S. Army Phase II SBIR award. We wish to thank TriQuest, Inc. for their generous donation of P4VP.