Application Of Cobalt-based Metal Organic Framework(MOF) Derivatives In Anode Materials For Lithium Ion Batteries

In this dissertation,cobalt-based MOF materials and cobalt-titanium bimetallic MOF were synthesized by solvothermal method.Then,these MOF precursors were pyrolyzed under inert gas to prepare carbon-coated cobalt titanate nanoparticles?CoTiO₃@C?and Ti-doped cobalt oxide nanoparticles and carbon hybrid?Ti-Doped-CoO@C?.Next,assembled them into lithium ion batterys as anode electrode.Finally,characterize the morphology,phase and electrochemical properties of the materials by related instruments.The first work,we use dimethylformamide?DMF?as solvent,cobalt chloride hexahydrate?CoCl₂·6H₂O?as cobalt source,and trimesic acid as ligands to synthesize cobalt-based MOF,Then,titanium is introduced into the MOF precursor by secondary solvothermal method using butyl titanate as titanium source.The precursor is calcined at a high temperature to obtain CoTiO₃@C hybrid,and then assembled into lithium ion battery as an anode.The corresponding reversible capacity is 630 mAh g^-11 at a current density of100 mA g^-1,and a reversible capacity of 610 mAh g^-11 was obtained after 1400 cycles at a current density of 2000 mA g^-1.In the second work,a cobalt-titanium bimetallic MOF precursor is synthesized by one-step solvothermal method.we use anhydrous methanol as a solvent,cobalt chloride hexahydrate?CoCl₂·6H₂O?as cobalt source,trimesic acid as ligands and butyl titanate as titanium source to synthesis Co-Ti-bimetallic MOF,and this MOF show a special octahedral structure.Calcining the precursor at 500?we can obtain Ti-Doped-CoO@C hybird.Thereafter,this special octahedral shape composite material is assembled into lithium ion battery as an anode.Besides,we performed an electrochemical test on the battery,when the current density is 200 mA g^-1,the specific capacity of the battery reaches about 1180 mAh g^-1.In this work,we test the CV curve at different scan rates,The contribution of pseudocapacitance capacitance in total capacity obtained through a series of calculations.The pseudocapacitance capacitance of Ti-Doped-CoO@C hybird reaches about 86.6%in the scan rate of 5 mVs^-1,which prove its excellent rate performance and cycle stability for lithium ion battery.