December 1 - 6, 2024
Boston, Massachusetts
Symposium Supporters
2024 MRS Fall Meeting & Exhibit
CH02.02.09

Investigation of Electrical Double Layers of Ionic Liquids in Graphene-Capped Liquid Cells by Multimodal Synchrotron Infrared Nanospectroscopy for Advanced Energy Storage Devices

When and Where

Dec 3, 2024
11:45am - 12:00pm
Sheraton, Third Floor, Gardner

Presenter(s)

Co-Author(s)

Zixuan Li1,Ka Chon Ng1,Maximilian Jaugstetter1,Xiao Zhao1,2,Miquel Salmeron1,3,Hans Bechtel1,Stephanie Gilbert Corder1

Lawrence Berkeley National Laboratory1,Stanford University2,University of California, Berkeley3

Abstract

Zixuan Li1,Ka Chon Ng1,Maximilian Jaugstetter1,Xiao Zhao1,2,Miquel Salmeron1,3,Hans Bechtel1,Stephanie Gilbert Corder1

Lawrence Berkeley National Laboratory1,Stanford University2,University of California, Berkeley3
Electrical double layer capacitors (EDLCs), often categorized as a subset of supercapacitors, are prominent energy devices owing to their advantages such as rapid charge/discharge processes, extremely long cycle life, and environmental and safety benefits. However, the generally low energy density of EDLCs hinders their broad application. A major strategy to improve the energy density of EDLCs involves employing electrolytes capable of high operation voltages. Ionic liquids (ILs) are a novel class of electrolytes typically composed of asymmetric organic cations and weakly coordinated anions. They appear to be ideal candidates to replace the diluted aqueous and organic electrolytes in current EDLCs for their wide electrochemical windows, which enable operation voltages much higher than conventional EDLCs and thus significantly improve the energy density. Moreover, the unique properties of ILs, including high thermal stability, non-flammability, high charge density, as well as their distinct EDL structure with oscillating ion concentration, not only make them safe and environmentally friendly options for EDLCs, but also present great possibilities for superior performance to traditional electrolytes. The implementation of ILs as electrolytes in EDLCs for enhanced performance and functionalities is contingent upon understanding the structure of IL EDLs, a knowledge gap that exists thus far. Here, we incorporate ILs in custom-made graphene-capped liquid cells, which allow for synchrotron infrared nanospectroscopy (SINS) investigation of IL EDLs, in combination with density functional theory (DFT) analysis and other atomic force microscopy (AFM) characterizations, including high-resolution structural imaging and Kelvin probe force microscopy (KPFM). This approach effectively correlates the chemical and vibrational bond information of IL EDLs with their nanoscale ion ordering and displacement behaviors, leading to a comprehensive understanding of IL EDLs that was previously inaccessible. The insights into IL EDL behaviors is expected to reveal the molecular-level dynamics corresponding to charge storage, thus providing valuable guidance for the design and creation of next-generation EDLCs based on novel IL-containing electrolytes.

Keywords

infrared (IR) spectroscopy | ion-solid interactions

Symposium Organizers

Ye Cao, The University of Texas at Arlington
Jinghua Guo, Lawrence Berkeley National Laboratory
Amy Marschilok, Stony Brook University
Liwen Wan, Lawrence Livermore National Laboratory

Session Chairs

Jinghua Guo
Liwen Wan

In this Session