Structural Regulation of Coordination Supramolecular Networks for Remarkable Lithium Storage

The search for high-energy and fast Li-ion transportation of lithium-ion battery (LIB) anode materials instead of graphite has aroused the wide attention of scientists. Coordination supramolecular networks (CSNs) are a class of active materials that can be used in energy storage devices because of their adjustable structural characteristics and various intermolecular forces. In this work, 1D-CoCSN {[Co3(stp)2(bpy)5(H2O)6]n} and 3D-CoCSN {[Co3(stp)2(bpy)(H2O)4]n} were synthesized by regulating the coordination reaction of 2-sulfoterephthalic acid monosodium salt (NaH2stp), 4,4 '- bipyridine (bpy), and cobalt ions. The X-ray photoelectron spectroscopy (XPS), ex situ Fourier transform infrared spectroscopy (FTIR), and density functional theory (DFT) analyses show that the carboxylic, sulfonic, and pyridine active groups of 1D-CoCSN are synergically involved in the storage process of lithium ions, and electrons could be transferred in the Z-shaped chain structure through the pi-d-pi conjugation effect. Hence, 1D-CoCSN exhibits a high capacity of 567 mAh g-1 after 200 cycles at 0.5 A g-1 and even runs 1000 cycles at 2 A g-1 with a capacity of 233 mAh g-1. Structural regulation of CSNs provides a new approach to designing LIB anodes with high capacity and stable cycling performance.

Automated summary

The search for high-energy and fast Li-ion transportation in lithium-ion battery (LIB) anode materials has attracted the attention of scientists. Coordination supramolecular networks (CSNs) have adjustable structures and various intermolecular forces, making them suitable for energy storage devices. In this study, 1D-CoCSN and 3D-CoCSN were synthesized using a coordination reaction. XPS, FTIR, and DFT analyses revealed that the active groups in 1D-CoCSN are involved in the storage process of lithium ions and can transfer electrons through the chain structure. 1D-CoCSN demonstrated a high capacity and stable cycling performance.