ChemRxiv
These are preliminary reports that have not been peer-reviewed. They should not be regarded as conclusive, guide clinical practice/health-related behavior, or be reported in news media as established information. For more information, please see our FAQs.
1/1

Phenazine–Based Covalent Organic Framework Cathode Materials with High Energy and Power Densities

preprint
submitted on 31.07.2019 and posted on 31.07.2019 by Edon Vitaku, Cara Gannett, Keith Carpenter, Luxi Shen, Hector Abruna, William Dichtel
Redox-active covalent organic frameworks (COFs) are promising materials for energy storage devices because of their high density of redox sites, permanent and controlled porosity, high surface areas, and tunable structures. However, the low electrochemical accessibility of their redox-active sites has limited COF-based devices either to thin films (<250 nm) grown on conductive substrates, or to thicker films (1 µm) when a conductive polymer is introduced into the COF pores. Electrical energy storage devices constructed from bulk microcrystalline COF powders, eliminating the need for both thin-film formation and conductive polymer guests, would offer both improved capacity and potentially scalable fabrication processes. Here we report on the synthesis and electrochemical evaluation of a new phenazine-based 2D COF (DAPH-TFP COF), as well as its composite with poly(3,4-ethylenedioxythiophene) (PEDOT). Both the COF and its PEDOT composite were evaluated as powders that were solution-cast onto bulk electrodes serving as current collectors. The unmodified DAPH-TFP COF exhibited excellent electrical access to its redox sites, even without PEDOT functionalization, and outperformed the PEDOT composite of a previously reported anthraquinone-based system. Devices containing DAPH-TFP COF were able to deliver both high energy (250 Wh/kg) and power densities (2950 W/kg), validating the promise of unmodified redox-active COFs that are easily incorporated into electrical energy storage devices.

Funding

ARO W911NF-15-1-0447

NSF ECCS-1542205

NSF DMR-1120296

History

Email Address of Submitting Author

wdichtel@northwestern.edu

Institution

Northwestern University

Country

USA

ORCID For Submitting Author

0000-0002-3635-6119

Declaration of Conflict of Interest

The authors declare no competing financial interest

Exports