title: Rapid and efficient redox processes within 2D covalent organic framework thin films.
abstract: Two-dimensional covalent organic frameworks (2D COFs) are ideally suited for organizing redox-active subunits into periodic, permanently porous polymer networks of interest for pseudocapacitive energy storage. Here we describe a method for synthesizing crystalline, oriented thin films of a redox-active 2D COF on Au working electrodes. The thickness of the COF film was controlled by varying the initial monomer concentration. A large percentage (80-99%) of the anthraquinone groups are electrochemically accessible in films thinner than 200 nm, an order of magnitude improvement over the same COF prepared as a randomly oriented microcrystalline powder. As a result, electrodes functionalized with oriented COF films exhibit a 400% increase in capacitance scaled to electrode area as compared to those functionalized with the randomly oriented COF powder. These results demonstrate the promise of redox-active COFs for electrical energy storage and highlight the importance of controlling morphology for optimal performance.
authors: Department of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, Ithaca, New York 14853-1301, United States.
authors: Catherine R
authors: CR
authors: DeBlase
authors: Department of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, Ithaca, New York 14853-1301, United States.
authors: Kenneth
authors: K
authors: Hernández-Burgos
authors: Department of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, Ithaca, New York 14853-1301, United States.
authors: Katharine E
authors: KE
authors: Silberstein
authors: Department of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, Ithaca, New York 14853-1301, United States.
authors: Gabriel G
authors: GG
authors: Rodríguez-Calero
authors: Department of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, Ithaca, New York 14853-1301, United States.
authors: Ryan P
authors: RP
authors: Bisbey
authors: Department of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, Ithaca, New York 14853-1301, United States.
authors: Héctor D
authors: HD
authors: Abruña
authors: Department of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, Ithaca, New York 14853-1301, United States.
authors: William R
authors: WR
authors: Dichtel
keywords: covalent organic framework; electrochemistry; energy storage; nanoporous materials; polymer films; supercapacitors; surface science