Improving multifunctional behavior in structural electrolytes through copolymerization of structure- and conductivity-promoting monomers

Polymer electrolytes were developed to improve simultaneous demonstration of mechanical and electrochemical properties. Solvent-free random copolymers were synthesized using one monomer with poly(ethylene glycol) sidechains that promote lithium ion conduction and one crosslinking monomer that promotes high modulus. Sixty unique systems of monomer pairs were developed in this manner. The properties of the resulting copolymers were influenced by the monomer ratio and chemistry. The copolymers consistently exhibited improved electrochemical-mechanical multifunctionality with respect to the analogous homopolymers. The most promising systems included highly conductive components paired with highly structural components, suggesting that improved multifunctionality may be achieved through interpenetrating multicomponent systems in which each component demonstrates high efficiency in a single property. Electrochemical, mechanical, and viscoelastic properties are discussed with respect to composition and the glass transition temperature. Modeling of conductivity and modulus was employed to enable prediction of copolymer properties based on the ratio and properties of the constituents.