Converting a Metal-Coordinating Polymer to a Polymerized Ionic Liquid Improves Li+ Transport

James T Bamford; Leo W Gordon; Raphaële J Clément; Rachel A Segalman

doi:10.1021/acsmacrolett.4c00704

Converting a Metal-Coordinating Polymer to a Polymerized Ionic Liquid Improves Li⁺ Transport

ACS Macro Lett. 2025 Jan 3:87-92. doi: 10.1021/acsmacrolett.4c00704. Online ahead of print.

Authors

James T Bamford^{1

2}, Leo W Gordon^{1

3}, Raphaële J Clément^{1

3}, Rachel A Segalman^{1

2}

Affiliations

¹ Materials Department, University of California, Santa Barbara, California 93106, United States.
² Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States.
³ Materials Research Laboratory, University of California, Santa Barbara, California 93106, United States.

PMID: 39749941
DOI: 10.1021/acsmacrolett.4c00704

Abstract

Solid polymer electrolytes (SPEs) with mechanical strength and reduced flammability may also enable next-generation Li⁺ batteries with higher energy densities. However, conventional SPEs have fundamental limitations in terms of Li⁺ conductivity. While an imidazole functionalized polymer (PMS-Im) has been previously shown to have ionic conductivity related to the imidazole-Li⁺ coordination, herein we demonstrate that quaternization of this polymer to form an analogous imidazolium functionalized polymer (PMS-Im⁺) more efficiently solvates lithium salts and plasticizes the polymer. In addition, inverse Haven ratios as high as 10 indicate positively correlated Li⁺ transport, possibly due to percolation of nanochannels that significantly improve battery-relevant conductivity. From these combined effects, Li⁺ conductivity in PMS-Im⁺ (2.1 × 10^-5 S/cm) is over an order of magnitude greater than in PMS-Im at 90 °C (1.6 × 10^-6 S/cm).