Phenanthroline Covalent Organic Framework Electrodes for High Performance Zinc-ion Supercapattery

by W. Wang, V. S. Kale, Z. Cao, S. Kandambeth, W. Zhang, J. Ming, P. Parvatkar, E. Abou-Hamad, O. Shekhah, L. Cavallo, M. Eddaoudi, H. N. Alshareef
Year: 2020 DOI: 10.1021/acsenergylett.0c00903

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ACS Energy Lett. 

Abstract

Aqueous zinc-ion batteries and capacitors are potentially competitive grid-scale energy storage devices due to their great features such as safety, environmental friendliness, and low cost. Herein, a completely new topological hexagonal phenanthroline covalent organic framework (PA-COF) structure was synthesized and introduced in zinc-ion supercapatteries (ZISs) for the first time. Our as-synthesized PA-COF shows a high capacity of 247 mAh g-1 at a current density of 0.1 A g-1, with only 0.38% capacity decay per cycle during 10000 cycles at a current density of 1.0 A g-1. Although covalent organic frameworks (COFs) are attracting a great attention in many fields, our PA-COF has been synthesized using a new strategy involving the condensation reaction of hexaketocyclohexanone and 2, 3, 7, 8-phenazinetetramine. Detailed mechanistic investigations, through experimental and theoretical methods, reveal that the phenanthroline functional groups in PA-COF are the active zinc ion storage sites. Furthermore, we provide evidence for the co-intercalation of Zn2+ (60%) and H+ (40%) into PA-COF using inductively coupled plasma atomic emission spectroscopy and deuterium solid-state nuclear magnetic resonance (NMR). We believe that this study opens a new avenue for COF material design for zinc-ion storage in aqueous ZISs.