Block polymer (BP) electrolytes are appealing alternatives to liquid, gel, or homopolymer systems because their mechanical, thermal, and conductive properties are decoupled such that enhanced stability and performance are achievable. Two BP approaches described herein are single-ion doping and homopolymer blending. In the doping approach, a self-doped diblock terpolymer electrolyte, in which the salt anions are attached covalently to the polymer, was designed such that one block was composed of a high modulus material and the other block consisted of both ion-conducting and self-doping monomer segments. The self-doped block polymers were synthesized with a series of self-doped lithium concentrations (by altering the relative amounts of ion-conducting and self-doping monomer segments). Small-angle X-ray scattering results suggested that all self-doped block polymers exhibited ordered nanostructures. AC impedance spectroscopy and DC polarization were used to evaluate the conducting properties of the electrolyte (ionic conductivity and transference number), and the conductivities increased with self-doping ratio. Using our understanding of the relationship between morphology, ion content, and ion transport, the composition of the self-doped BPs was manipulated to improve lithium ion conductivity. In the blending approach, polystyrene-b-poly(oligo-oxyethylene methacrylate) [PS-b-POEM] BPs were blended with a more mobile, ion-conducting POEM homopolymer; the blends then were doped with lithium salts. By adding homopolymers of different molecular weights, wet brush or dry brush regimes were achieved, as confirmed via neutron reflectometry. The wet brush polymer blends increased the mobility of both the polymer and lithium as suggested by the reduction of Tg,POEM and via line narrowing in variable temperature Li-7 solid-state nuclear magnetic resonance measurements, respectively. However, the dry brush blend demonstrated an overall higher ionic conductivity, likely due to the presence of homopolymer-rich ion channels.

Single-ion doping and homopolymer blending approaches to improved ion-transport in block polymer electrolyte materials

Macromolecular Chemistry: The Second Century

[Author Benefits](https://scimeetings.acs.org/?utm_source=pubs_content_marketing&utm_medium=website&utm_campaign=0320_MCF_NPI_Launch_Spring_Homepage&ref=pubs_content_marketing)

[How to use SciMeetings](https://storage.googleapis.com/dl.morressier.com/acs/SciMeetings-ACSSpring2020-HowToGuide_M3020-Final.pdf)

[Frequently Asked Questions](https://storage.googleapis.com/dl.morressier.com/acs/SciMtng_ACSNMSp2020_FAQ_M3120_Final.pdf)

ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.