Proton Conducting Sulfonated Poly(Ionic Liquid) Block Copolymers

Rui Sun, Mahesh Agrawal, Kenneth Neyerlin, Joshua Snyder, Yossef Elabd

Research output: Contribution to journalArticlepeer-review

6 Scopus Citations


Herein, we report the synthesis of proton-conducting sulfonated poly(ionic liquid) block copolymers (S-PILBCPs) containing one block with sulfonic acid (sulfonated styrene, SS) and the other with an IL moiety (vinylbenzylmethylimidazolium bis(trifluoromethylsulfonyl)imide, VBMIm-TFSI) using reversible addition-fragmentation chain-transfer (RAFT) polymerization and post-polymerization modifications (i.e., functionalization, anion exchange reactions, and sulfonation). The S-PILBCPs uniquely conjoin the SS block with mobile protons (H+) and the PIL block with mobile anions (TFSI-), where multiple highly desired properties, including high proton conductivity (from the SS block), and high IL-philicity and oxygen solubility (from the PIL block) can exist compartmentally within a microphase separated morphology (evidenced by differential scanning calorimetry (DSC) and small-angle X-ray scattering (SAXS)). High ion conductivity of 79.7 mS/cm at a PIL block composition of 21.6 mol % was observed at 80 °C and 90% relative humidity (RH) (comparable to the benchmark Nafion ionomer). This work successfully demonstrates the design of S-PILBCPs as a new material platform and showcases its promise as an ionomer for proton exchange membrane fuel cells (PEMFCs) as they simultaneously and compartmentally combine proton conductivity and oxygen solubility. These benefits have recently been leveraged to achieve substantial improvement in oxygen reduction reaction (ORR) activity and subsequently fuel cell performance.

Original languageAmerican English
Pages (from-to)6716-6729
Number of pages14
Issue number15
StatePublished - 2022

Bibliographical note

Publisher Copyright:
© 2022 American Chemical Society.

NREL Publication Number

  • NREL/JA-5900-84064


  • anion exchange reactions
  • functionalization
  • reversible addition-fragmentation chain-transfer polymerization
  • sulfonated poly(ionic liquid) block copolymers
  • sulfonation
  • sulfonic acid


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