Synthesis And Characterization Of Metal Compounds/carbon Nanofibers Study On Lithium Storage Performance

Lithium-ion batteries(LIBs)have become the most widely used and highly efficient energy equipment due to their high energy density,no memory effect,safety and environmental protection,and are also the main energy source for electronic products on the market.The commonly used graphite anode is limited by its lower theoretical capacity,and cannot meet the demand for high-efficiency energy storage equipment in the future.However,metal compounds have received extensive attention from researchers due to their high theoretical capacity,wide distribution,safety and environmental protection.However,when metal compounds are used as electrode materials,large volume changes during charging and discharging are likely to cause rapid capacity decay,which severely limits the development of anode materials.Researchers have found that the prepared nano-scale electrode materials and the introducing carbon materials can effectively improve the lithium storage performance of metal compounds.Based on this,this thesis prepared two metal compound/carbon composite nanomaterials by compounding with one-dimensional carbon nanofibers and investigated their lithium storage performance as anode materials for LIBs.The specific research contents are as follows:(1)The preparation of Fe₃O₄@CNFs and the investigation of its lithium storage propertiesFe₃O₄nanoparticles were successfully embedded into one-dimensional carbon nanofibers by solvothermal method and electrospinning technique as well as the subsequent high temperature carbonization.The structure and morphology of the obtained Fe₃O₄@CNFs were then investigated.The lithium storage performance of the Fe₃O₄@CNFs as anode materials of LIBs was also investigated by electrochemical performance test,which showed that the Fe₃O₄@CNFs-0.4 had a reversible capacity of 930m Ah g^-1 after 160 cycles at a current density of 100 m A g^-1 and the coulombic efficiency is close to 100%.In particular,the discharge capacity can still be maintained at 173 m Ah g^-1after 900 cycles at a high current density of 2 A g^-1,showing excellent cycle stability.(2)The preparation of Sb₂O₃@CNFs and the investigation of its lithium storage propertiesSb₂O₃@CNFs were prepared by electrospinning and annealing process using triphenylantimony as Sb source and polyacrylonitrile as carbon skeleton.The crystal structure and morphology of the Sb₂O₃@CNFs were characterized by XRD,SEM,TEM and XPS.The synthesized Sb₂O₃@CNFs-0.35 was used as an anode material for LIBs and Li-based dual-ion batteries(LDIBs),showing excellent electrochemical performance,including high reversible capacity(?360 m Ah g^-1 at 1 A g^-1 for LIBs and 233.5 m Ah g^-1 at0.2 A g^-1 for LDIBs)and favorable cycling stability(over 800 cycles for LIBs and 100cycles for LDIBs).