Covalent organic frameworks (COFs) are 2D or 3D porous crystalline polymers with tailorable pore sizes and structures. 2D COFs enable charge transport between polymer sheets due to their layered π-stacked structures, which makes them promising candidates for electronic applications. This is especially true for redox-active COFs, which are able to store charge both in the electrochemical double layer and through surface-bound Faradaic (pseudocapacitive) processes, which depend on the material’s surface area, conductivity, and density of redox sites. However, because most established COFs exhibit poor conductivity, their use has been limited to those prepared as very thin films (&lt;200 nm) or few-layer sheets. Our group has recently developed a composite system of a quinone-based redox-active COF infiltrated with a conductive polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), which allows growth of thick films (&gt;1µm) and quantitative electrochemical accessibility of the quinone moieties, resulting in significant improvements in volumetric energy and power density compared to unmodified COF films. This system works exceptionally well in aqueous electrolytes because the redox-potential of the quinones of the COF matches the window at which PEDOT is conductive. Yet, this potential overlap is not observed in organic electrolytes, which exhibit wider operating potential windows compared to their aqueous counterparts. Here, we introduce a dimethyl-dihydrophenazine moiety as a new redox-active group with matching potential to PEDOT’s conductive window in organic electrolytes, enabling the use of these composite systems as electrode materials even at high potentials. After the preparation of the framework, its pores are then functionalized with PEDOT through the polymerization of EDOT. We are currently investigating how these all-organic based composite systems lead to high charging rates, high capacitance, and high performance over wide operating potential windows.

Conducting polymer–modified covalent organic framework with overlapping potentials in organic electrolytes

256th National Meeting (2018)

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