Fabrication Of Metal-calixarene Cluster Supported Composite Nanofibers By Electrospining

Electrospinning is a kind of fiber manufacturing process which enables polymer to spinning under the high-voltage electrostatic field.The preparation method is simple,the cost is low and the fiber can reach the micro-nano-scale.At the same time,the carbon nanofibers obtained by pre-oxidation and carbonization have also been used in lithium-ion batteries because of their continuous and interconnected structure,which not only increases the electron conduction pathway,but also has a large specific surface area.It provides high ion contact area and excellent lithium ion storage performance.Metal-thiacalixarene cluster compounds are special S-containing metal-organic-frameworks,and they are promising precursors to fabricate carbon encapsulated metal sulfides nanoparticles by direct annealing in N₂,which shows relatively good electrical conductivities,excellent thermal stabilities and high theoretical capacities.In this paper,metal-thiacarene clusters were combined with electrospinning technology to prepare metal calixarene cluster nanofibers,and the N-doped carbon nanofiber composites loaded with Co₉S₈ nanoparticles（N-doped CoO@Co₉S₈@CNFs）were prepared by stabilizing them and carbonization in inert atmosphere.The composites were characterized by scanning electron microscopy（SEM）,transmission electron microscopy（TEM）,X-ray diffraction（XRD）and X-ray photoelectron spectroscopy（XPS）.The composite was used as electrode and its application in lithium ion battery was studied.The specific work is as follows.1.The metal-thiacarene cluster composite nanofibers were prepared by electrospinning technique with Co₃₂ clusters as loading materials,PAN as spinning carrier.The nanofiber felt was preoxidized and carbonized to obtain N-doped CoO@Co₉S₈@CNFs.CoO@Co₉S₈@C and CNFs as contrast materials were prepared by calcining Co₃₂ clusters and PAN nanofilbers in N₂respectively.The materials were characterized by SEM,TG,TEM,XRD,XPS and their properties in lithium-ion batteries were also explored for the first time.It is found that N-doped CoO@Co₉S₈@CNFs has better rate performance,coulomb efficiency and cyclic stability.On the basis of the previous,the single polymer spinning carrier was replaced with polymer blend（PAN/PMMA）.The functionalized carbon nanofiber materials with specific morphologies of porous,multi-channel or multi-gap were prepared by electrospinning and subsequent heat treatment.By changing the ratio of PMMA in precursor solution,the effects of PMMA addition on fiber morphology and electrochemical properties of carbon nanofiber composites were studied,and compared with the carbon nanofibers prepared by single spinning carrier.The lithium electric properties of carbon nanofiber composites prepared with PAN:PMMA=1:1 as spinning auxiliaries are more excellent.2.The highest nuclear coordination cage compounds-Co₄₈ cage clusters were selected as the loading material.The Co₄₈ crystal is a sulfur-nitrogen cluster with macroporous structure.A group of composites were prepared by using PAN:PMMA=10:0,1:1 and 7:3 as spinning carriers,respectively.A group of composites were prepared with PAN:PMMA=10:0,1:1 and 7:3 as spinning carriers respectively.The carbon nanofiber composites obtained by heat treatment were characterized and used as electrode materials in lithium ion storage.The results were compared with the products calcined in nitrogen atmosphere of Co₄₈ crystal.And explore whether the addition of PMMA will optimize the electrochemical properties of the system.The result is that the larger proportion of the PMMA,the better electrochemical performance of the composite.