3D\nGraphene Functionalized by Covalent Organic Framework Thin Film as\nCapacitive Electrode in Alkaline Media

Abstract

To\nharness the electroactivity of anthraquinone as an electrode material,\na great recent effort have been invested to composite anthraquinone\nwith carbon materials to improve the conductivity. Here we report\non a noncovalent way to modify three-dimensional graphene with anthraquinone\nmoieties through on-surface synthesis of two-dimensional covalent\norganic frameworks. We incorporate 2,6-diamino-anthraquinone moieties\ninto COF through Schiff-base reaction with benzene-1,3,5-tricarbaldehyde.\nThe synthesized COF -graphene composite exhibits large specific capacitance\nof 31.7 mF/cm². Long-term galvanostatic charge/discharge\ncycling experiments revealed a decrease of capacitance, which was\nattributed to the loss of COF materials and electrostatic repulsion\naccumulated during charge–discharge circles which result in\nthe poor electrical conductivity between 2D COF layers.