Synthesis Of Anthracene Functionalized Metal-Organic Framework(MOFs) And Application As Anode Material For Lithium Ion Batteries

Organic electrode materials have become the preferred materials for the development of next-generation lithium-ion batteries with high capacity and stable performance due to their advantages of renewable,green,low cost and high capacity.In view of the difficulties faced by organic electrode materials,such as high solubility,poor conductivity and low density,the introduction of active conjugated organic small molecules into polymers such as Metal-Organic Frameworks（MOFs）by chemical methods can effectively solve the above problems and improve the reversible capacity and cycle performance of batteries.Herein,organic anthracene molecules were introduced into the framework of terpyridine ligands,and a series of MOFs（Cu-TPF,Mn-TPYAN and Cd-TPYAN）with multiple charge-discharge active sites were designed and synthesized.Their structures were characterized,and they were used as anode materials Li-ion batteries,and Cu-TPF,Mn-TPYAN electrochemical properties were studied in detail.The specific research contents and results are as follows:（1）Single crystal diffraction data and structural analysis confirm that Cu-TPF is a supramolecular framework with pores composed of dinuclear Cu（II）coordination units through theπ-πinteraction.Cd-TPYAN and Mn-TPYAN are three-dimensional coordination polymers with pores,and organic anthracene molecules are arranged in parallel in the pores.（2）Cu-TPF contains multiple charge-discharge active sites,such as carbonyl,carboxyl,hydroxyl,pyridine nitrogen and conjugated aromatic ring,etc.The electrochemical performance test results show that the charge-discharge capacity of the Cu-TPF-01 electrode can be up to 810.1 m Ah g^-1 after 170 cycles at a current density of 100 m A g^-1.When the current density is increased to 5000,10000 and 20000 m A g^-1,the charge-discharge capacity of Cu-TPF-01 electrode can reach 560.5,523.5 and500.3 m Ah g^-1,respectively.In addition,we conducted a series of characterizations on the electrodes before and after cycling,as well as during the charging and discharging processes.The possible charging and discharging mechanism were discussed.Cu-TPF-01 electrode has ultra-high specific capacity,outstanding cycle stability and superior rate performance.（3）Mn-TPYAN has multiple charge and discharge active sites（such as carboxyl,pyridine ring and anthracene ring）,large conjugated ligand skeleton and ordered pore structure.When Mn-TPYAN-01 is used as the anode material of LIBs,it has excellent cycle stability.After 260 cycles,the Mn-TPYAN electrode can deliver the reversible capacity of 650 m Ah g^-1 at the current density of 100 m A g^-1.When the current density is increased to 2000 m A g^-1,the Mn-TPYAN electrode can maintain the reversible capacity of 250.1 m Ah g^-1 after 2000 cycles.In addition,the CV kinetic analysis results show that the lithium storage mechanism of Mn-TPYAN-01 electrode is a synergistic process consisting of diffusion behavior and capacitance control.