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Surface and Conductivity Characterization of Layered Organic Ionic Plastic Crystal (OIPC)-Polymer Films

journal contribution
posted on 2024-02-08, 01:06 authored by Minkyung Kang, Frederick Nti, Jun Rao, Nicolas Goujon, Mingyu HanMingyu Han, George Greene IVGeorge Greene IV, Xiaoen Wang, Maria Forsyth, Patrick C Howlett
Organic ionic plastic crystals (OIPCs) are attractive solid electrolyte materials for advanced energy storage systems owing to their inherent advantages (e.g., high plasticity, thermal stability, and moderate ionic conductivity), which can be further improved/deteriorated by the addition of polymer or metal oxide nanoparticles. The role of the nanoparticle/OIPC combinations on the resultant interphase structure and transport properties, however, is still unclear due to the complexity within the composite structures. Herein, we demonstrate a systematic approach to specifically interrogating the interphase region by fabricating layered OIPC/polymer thin films via spin coating and correlating variation in the ionic conductivity of the OIPC with their microscopic structures. In-plane interdigitated electrodes have been employed to obtain electrochemical impedance spectroscopy (EIS) spectra on both OIPC and layered OIPC/polymer thin films. The thin-film EIS measurements were evaluated with conventional bulk EIS measurements on the OIPC pressed pellets and compared with EIS obtained from the OIPC-polymer composites. Interactions between the OIPC and polymer films as well as the morphology of the film surfaces have been characterized through multiple microscopic analysis tools, including scanning electron microscopy, energy-dispersive X-ray spectroscopy, atomic force microscopy, and optical profilometry. The combination of EIS analysis with the microscopic visualization of these unique layered OIPC/polymer thin films has confirmed the impact of the OIPC-polymer interphase region on the overall ionic conductivity of bulk OIPC-polymer composites. By changing the chemistry of the polymer substrate (i.e., PMMA, PVDF, and PVDF-HFP), the importance of compatibility between the components in the interphase region is clearly observed. The methods developed here can be used to screen and further understand the interactions among composite components for enhanced compatibility and conductivity.

Funding

M.K. is the recipient of an Australian Research Council (ARC) Discovery Early Career Researcher Award (DECRA, project number DE220101105), funded by the Australian Government. The authors gratefully express their appreciation to the US Army Research Office (ARO) for financial support (W911NF1710560) and Prof. W. A. Henderson for insightful discussion throughout the project.

History

Publication Date

2023-12-13

Journal

ACS Applied Materials and Interfaces

Volume

15

Issue

49

Pagination

10p. (p. 57750-57759)

Publisher

American Chemical Society

ISSN

1944-8244

Rights Statement

© 2023 American Chemical Society