Abstract
Confined ionic liquids in hydrophilic porous media have disrupted lattices and can be divided into two layers: An immobile ion layer adheres to the pore surfaces, and an inner layer exhibits faster mobility than the bulk. In this work, we report the first study of ionic liquids confined in block copolymer-based porous carbon fibers (PCFs) synthesized from polyacrylonitrile-block-polymethyl methacrylate (PAN-b-PMMA). The PCFs contain a network of unimodal mesopores of 13.6 nm in diameter and contain more hydrophilic surface functional groups than previously studied porous carbon. Elastic neutron scattering shows no freezing point for 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4) confined in PCFs down to 20 K. Quasi-elastic neutron scattering (QENS) is used to measure the diffusion of [BMIM]BF4 confined in PCFs, which, surprisingly, is 7-fold faster than in the bulk. The unprecedentedly high ion diffusion remarks that PCFs hold exceptional potential for use in electrochemical catalysis, energy conversion, and storage.
| Original language | English |
|---|---|
| Pages (from-to) | 36980-36986 |
| Number of pages | 7 |
| Journal | ACS Applied Materials and Interfaces |
| Volume | 14 |
| Issue number | 32 |
| DOIs | |
| State | Published - Aug 17 2022 |
Funding
This article contains studies supported by the National Science Foundation under grant no. DMR-1752611 through the CAREER award and the American Chemical Society Petroleum Research Foundation Doctoral New Investigator Award. Work at ORNL’s Spallation Neutron Source was sponsored by the Scientific User Facilities Division Office of Basic Energy Sciences, US Department of Energy. The Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for US DOE under contract no. DEAC05-00OR22725. Experiments on HFBS at NIST Center for Neutron Research (NCNR) were supported in part by the National Science Foundation under agreement no. DMR-2010792. Certain commercial material suppliers are identified in this paper to foster understanding. Such identification does not imply recommendation or endorsement by the National Institute of Standards and Technology, nor does it imply that the materials or equipment identified are necessarily the best available for the purpose. This article contains studies supported by the National Science Foundation under grant no. DMR-1752611 through the CAREER award and the American Chemical Society Petroleum Research Foundation Doctoral New Investigator Award. Work at ORNL’s Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, US Department of Energy. The Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for US DOE under contract no. DEAC05-00OR22725. Experiments on HFBS at NIST Center for Neutron Research (NCNR) were supported in part by the National Science Foundation under agreement no. DMR-2010792. Certain commercial material suppliers are identified in this paper to foster understanding. Such identification does not imply recommendation or endorsement by the National Institute of Standards and Technology, nor does it imply that the materials or equipment identified are necessarily the best available for the purpose.
| Funders | Funder number |
|---|---|
| Scientific User Facilities Division | |
| Scientific User Facilities Division Office of Basic Energy Sciences | |
| National Science Foundation | DMR-1752611 |
| U.S. Department of Energy | DEAC05-00OR22725, DMR-2010792 |
| National Institute of Standards and Technology | |
| Basic Energy Sciences | |
| Oak Ridge National Laboratory | |
| American Chemical Society Petroleum Research Fund |
Keywords
- block copolymer
- ion diffusion
- porous carbon fiber
- quasielastic neutron scattering
- room temperature ionic liquid