Recently, the Bin Deshan/Li Dan team of Jinan University published a research paper entitled "Immobilizing Redox-Active Tricycloquinazoline into a 2D Conductive Metal-Organic Framework for Lithium Storage" in the international authoritative academic journal Angewandte Chemie.
Lithium-ion batteries have important applications in mobile electronic devices, electric vehicles, energy storage power stations, smart grids and other fields, and their research has received widespread attention in recent years. Because of its rich resources, environmental friendliness, designable structure and high theoretical capacity, organic electrode materials have aroused the strong interest of researchers, but the shortcomings of organic electrode materials that are easily soluble in organic electrolytes, low conductivity, and slow reaction kinetics restrict their application.
The team of Professors Bin Deshan and Li Dan designed and synthesized Cu-HHTQ, a two-dimensional conductive material based on the nitrogen-rich molecule tricyclic quinazoline (TQ), and studied its application in lithium-ion batteries. TQ as a nitrogen-rich conjugate thick ring molecule has good redox activity, combined with the redox activity of the coordination node CuO4, Cu-HHTQ obtained multiple redox activity sites, realizing the application as a high specific capacity lithium-ion battery anode material.
The long-range ordered structure of the two-dimensional conductive MOF makes it insoluble in the electrolyte, has high cyclic stability, and its porosity and high conductivity can accelerate the transmission of ions and electrons, so it may become an electrode material with high magnification properties. The study found that due to the high conductivity, porous characteristics and multi-electron redox characteristics of Cu-HHTQ, it shows high specific capacity, good magnification performance and excellent cycle stability as a lithium-ion battery anode material. Cu-HHTQ has a reversible specific capacity of 657.6 mAhg-1 at a current density of 600 mAg-1, and still has a capacity retention rate of 83% after 200 cycles of charge and discharge, which is at a high level among the conductive MOF materials reported today.
In order to explore the electrochemical lithium storage mechanism of the obtained conductive materials, the researchers conducted electrochemical tests on the TQ molecule and studied its lithification reaction process through theoretical calculations, verifying for the first time that TQ has 9 electron redox activity. Constructing TQ in a conductive metal-organic framework Cu-HHTQ can effectively increase its specific capacity as an anode material for lithium-ion batteries.
As a bottom-up material, conductive MOF provides an effective platform for fixing redox active molecules. The design and synthesis of organic electrode materials based on the novel redox active unit TQ deserve further study, and it has been proved to be an effective strategy to assemble multiple redox active parts into high-performance electrode materials through the principle of grid chemistry.
The first author of the paper is Yan Jie, a postdoctoral fellow of Jinan University, and the corresponding author is Professors Bin Deshan and Li Dan of the School of Chemistry and Materials, and the research work has been funded by the National Natural Science Foundation of China and the China Postdoctoral Science Foundation.
Source: Jinan University
Thesis Link:
https://doi.org/10.1002/anie.202110373