Metal-organic Frame Composites As Anodes For Lithium-ion Batteries And Analysis Of Their Electrochemical Performance

In recent years,lithium-ion batteries have been widely used in mobile electronic devices such as mobile phones,computers,remote control and electric cars due to their high operating voltage,high specific energy and long cycle life.As a traditional negative electrode material,graphite has always been a hot spot for lithium ion negative electrode materials.However,because graphite expands rapidly during the charge and discharge of lithium ions,and graphene has high conductivity and cyclic stability,therefore,this graphite In this paper,MOFs/graphite and MOFs/graphene oxide composite anode materials were prepared using metal-organic frameworks?MOFs?as precursors.This method uses the hollow structure of MOFs to provide space to relieve strain and accommodate lithium insertion and extraction.The volume change improves the discharge capacity and cycle performance of lithium-ion batteries.The specific research content is as follows:?1?Co-MOFs/graphite and Ni-MOFs/graphite composites were synthesized by hydrothermal method,and the morphology,structure and electrochemical properties of the composites were analyzed.The research showed that The MOFs of the layer can form a structure similar to the SEI film,and the morphology and structure of graphite,including crystal planes and defects,have slight changes.Electrochemical test results show that because lithium ions can participate in electrochemical reactions on a limited graphite crystal plane,the anodes of 15%Co-MOFs and 10%Ni-MOFs modified graphite have a more reversible lithium ion insertion and extraction process,Lower charge transfer resistance and faster lithium ion diffusion rate,after 50 cycles,the capacity retention rate is the highest,exceeding 80%.?2?The graphene oxide was prepared by the Hummers method,the graphene oxide was calcined,and the Co-MOFs/graphene oxide and Ni-MOFs/graphene oxide composite materials were synthesized by the hydrothermal method.The structure and morphology of the composite materials Characterization was performed and the electrochemical performance of the materials used in lithium-ion batteries was tested.The results show that when Co-MOFs:graphene oxide is 1:1.5 and Ni-MOFs:graphene oxide is 1:1,after 500 cycles,compared with other ratio batteries,the capacity retention rate is the highest,and the maximum discharge capacity is up to 873.13 mAh·g^-11 and 635 mAh·g^-1.