A tris(terpyridine) ligand-based metal coordination nanosheet as electrode material with good supercapacitor performance

Abstract

In this work, through a facile liquid–liquid (L–L) interfacial-assisted synthesis at room temperature, a new two-dimensional (2D) metal coordination nanosheet Co-TPY-LB has been synthesized by the coordination between Co2+ ion and 1,3,5-tris(4′-tripyridinylphenyl)benzene (Tris-tpy). The flat and smooth sheet structure with a thickness of 83.3 nm and a hexagonal structure with a lattice spacing of about 0.206 nm for the as-fabricated nanosheet Co-TPY-LB has been identified by AFM and HRTEM respectively, providing a large number of redox sites and ion diffusion channels. The fabricated Co-TPY-LB have been used as electrodes and exhibit the highest capacity of 2741.5 F g−1 at the current density of 1 A g−1, an excellent cycling stability with 97.6% capacity retention after 1000 cycles at the current density of 10 A g−1. Meanwhile, the assembled asymmetric supercapacitor with Co-TPY-LB as the positive electrode shows a high energy density 73.6 Wh kg−1 at a power density of 4800 W kg−1 as well as an excellent cycle stability of 92.9% capacity retention after 5000 cycles. Our work provides a controllable synthesis for the construction of 2D metal coordination nanosheet to overcome some defects of 2D nanosheet by traditional synthesis, leading such bottom-up nanosheet to a promising application in energy storage.