skip to main content
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Spontaneous Ionic Polarization in Ammonia-Based Ionic Liquid [Spontaneous Ionic Polarization in Ionic Liquid]

Abstract

Ionic liquids and gels have attracted attention for a variety of energy storage applications, as well as for high performance electrolytes for batteries and super-capacitors. Although the electronic structure of ionic electrolytes in these applications is of practical importance for device design and improved performance, the understanding of the electronic structure of ionic liquids and gels is still at an early stage. Here we report soft x-ray spectroscopic measurements of the surface electronic structure of a representative ammonia-based ionic gel (DEME-TFSI with PSPMMA- PS copolymer). We observe that near the outermost surface, the area of the anion peak (1s N - core level in TFSI) is relatively larger than that of the cation peak (N + in DEME). This spontaneous ionic polarization of the electrolyte surface, which is absent for the pure ionic liquid without copolymer, can be directly tuned by the copolymer content in the ionic gel, and further results in a modulation in work function. Finally, these results shed new light on the control of surface electronic properties of ionic electrolytes, as well as a difference between their implementation in ionic liquids and gels.

Authors:
ORCiD logo [1];  [2];  [2];  [3];  [2];  [2];  [4];  [2]
  1. Pohang Accelerator Lab., Pohang (South Korea); SLAC National Accelerator Lab., Menlo Park, CA (United States)
  2. SLAC National Accelerator Lab., Menlo Park, CA (United States)
  3. Stanford Univ., Stanford, CA (United States)
  4. SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States)
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1452771
Grant/Contract Number:  
[AC02-76SF00515]
Resource Type:
Accepted Manuscript
Journal Name:
ACS Applied Energy Materials
Additional Journal Information:
[ Journal Volume: 1; Journal Issue: 6]; Journal ID: ISSN 2574-0962
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; DEME-TFSI; in situ bias; ionic gel; photoemission spectroscopy; self-polarization; surfaces and interface property

Citation Formats

Kim, Ki-jeong, Yuan, Hongtao, Jang, Hoyoung, Kim, Bongju, Seoung, Donghoon, Hikita, Yasuyuki, Hwang, Harold Y., and Lee, Jun -Sik. Spontaneous Ionic Polarization in Ammonia-Based Ionic Liquid [Spontaneous Ionic Polarization in Ionic Liquid]. United States: N. p., 2018. Web. doi:10.1021/acsaem.8b00383.
Kim, Ki-jeong, Yuan, Hongtao, Jang, Hoyoung, Kim, Bongju, Seoung, Donghoon, Hikita, Yasuyuki, Hwang, Harold Y., & Lee, Jun -Sik. Spontaneous Ionic Polarization in Ammonia-Based Ionic Liquid [Spontaneous Ionic Polarization in Ionic Liquid]. United States. doi:10.1021/acsaem.8b00383.
Kim, Ki-jeong, Yuan, Hongtao, Jang, Hoyoung, Kim, Bongju, Seoung, Donghoon, Hikita, Yasuyuki, Hwang, Harold Y., and Lee, Jun -Sik. Thu . "Spontaneous Ionic Polarization in Ammonia-Based Ionic Liquid [Spontaneous Ionic Polarization in Ionic Liquid]". United States. doi:10.1021/acsaem.8b00383. https://www.osti.gov/servlets/purl/1452771.
@article{osti_1452771,
title = {Spontaneous Ionic Polarization in Ammonia-Based Ionic Liquid [Spontaneous Ionic Polarization in Ionic Liquid]},
author = {Kim, Ki-jeong and Yuan, Hongtao and Jang, Hoyoung and Kim, Bongju and Seoung, Donghoon and Hikita, Yasuyuki and Hwang, Harold Y. and Lee, Jun -Sik},
abstractNote = {Ionic liquids and gels have attracted attention for a variety of energy storage applications, as well as for high performance electrolytes for batteries and super-capacitors. Although the electronic structure of ionic electrolytes in these applications is of practical importance for device design and improved performance, the understanding of the electronic structure of ionic liquids and gels is still at an early stage. Here we report soft x-ray spectroscopic measurements of the surface electronic structure of a representative ammonia-based ionic gel (DEME-TFSI with PSPMMA- PS copolymer). We observe that near the outermost surface, the area of the anion peak (1s N- core level in TFSI) is relatively larger than that of the cation peak (N+ in DEME). This spontaneous ionic polarization of the electrolyte surface, which is absent for the pure ionic liquid without copolymer, can be directly tuned by the copolymer content in the ionic gel, and further results in a modulation in work function. Finally, these results shed new light on the control of surface electronic properties of ionic electrolytes, as well as a difference between their implementation in ionic liquids and gels.},
doi = {10.1021/acsaem.8b00383},
journal = {ACS Applied Energy Materials},
number = [6],
volume = [1],
place = {United States},
year = {2018},
month = {5}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Save / Share: