Two-dimensional extended π-conjugated triphenylene-core covalent organic polymer

Abstract

Carbon-rich two-dimensional (2D) materials show significant potential in energy storage and conversion applications. A conjugated 2D covalent organic polymer (COP) with embedded triphenylene (TP) units was synthesized by Glaser–Hay cross-coupling and validated by Raman, IR, XPS and NMR spectroscopy. TP-COP exhibited a uniform pore size of 5.4 Å and laminar structure with an interlayer spacing of 3.8 Å, which could be mechanically exfoliated to yield few-layered nanosheets. Interfacial polymerization produced the continuous TP-COP films from quasi-monolayer to multilayer. As the anode materials of lithium batteries, TP-COP delivered large reversible capacity up to 1624 mA h g⁻¹, high charge rate, and good recycling ability. These properties are likely due to the presence of lithium ions in both the interspace of the expanded sp² moieties and the in-plane nanopores of TP-COP.