Synthesis Of MOFs By Mixed Ligands Strategy And Application For Lithium Battery

As an important component of coordination polymers（CPs）,Metal-organic frameworks（MOFs）have become a rapidly growing research field.It is widely used in gas storage,drug delivery,catalysis,sensing,proton conduction,renewable energy and many other fields because of its high specific surface area,adjustable pore size distribution various and morphological characteristics.In this paper,from the perspective of energy storage,five new metal-organic frameworks were successfully synthesized by the one-pot reaction method,and their crystal structures were determined by X-ray single-crystal diffraction.And the structure stability and thermal stability were characterized by powder X-ray diffraction（XRD）,infrared spectroscopy（IR）and thermogravimetric analysis（TGA）.Finally,the performance of metal organic rotaxane framework（MORF）-based composite polymer electrolytes and MOF-derived anode was investigated by electrochemical tests.Details are as follows:（1）Two metal-organic rotaxane frameworks,CUST-701 and CUST-702,were successfully synthesized by hydrothermal method with zinc ion as coordination center,[PR43]²⁺·2[NO₃]^-as the main ligand,and 2-H₂stp Na and 5-SSIPA as the auxiliary ligands,respectively.Subsequently,Li CUST-701 and Li CUST-702 were prepared by ion exchange treatment,which were compounded with PEO and Li TFSI to prepare composite polymer electrolytes.The results show that the addition of CUST-701 and CUST-702 can improve the ionic conductivity and guide the uniform deposition of Li⁺,suppress the growth of lithium dendrites,and improve the cycle life of all-solid-state batteries.（2）A new 3D metal-organic framework,CUST-705,was synthesized by solvothermal method with H₃BTB as the main ligand and 4,4’-AZPY as the auxiliary ligand.Then Co₃O₄@N-C was prepared by a two-step calcination strategy at different temperatures.The experimental results show that Co₃O₄@N-C can significantly improve the capacity as well as the cycling stability of the battery,with Co₃O₄@N-C-700 showing the best cycling stability.（3）Two new two-dimensional metal-organic networks,CUST-706 and CUST-707,were successfully synthesized by a one-pot method with 1,4-NDC and 4,4’-AZPY as organic linkers and cadmium and cobalt ions as coordination centers.Both of them have similar 2D network structures and good thermal stability.