Preparation Of N-doped Porous Fiber And Their Properties Research Of Sodium Storage

In recent years,lithium-ion batteries are widely used in new energy vehicles and portable electronic equipment because of their high voltage,low self-discharge,high energy density and long-life cycling performance.However,the shortage of lithium storage leads to the continuous increase in the cost of lithium-ion batteries,and it is urgent to find other energy storage systems that can replace LIBs.Metal lithium and sodium belong to the same main family,and their properties are similar and the reserves are relatively abundant.Therefore,sodium ion batteries have gradually entered people’s field of vision.At the same time,sodium-ion batteries also have similar problems as lithium batteries,such as poor cycling performance and low capacity due to expansion and shedding of electrode materials.Therefore,the size control and the preparation of complex is generally used to improve the storage performance.Based on the above ideas,a d regular porous nanofiber carbon material（NRP-CNF）and a porous nickel disulfide nanofiber material（NiS₂NP/p-CNF）were designed and synthesized by electrospinning technology,and showing excellent electrochemical properties in sodium storage system.The main research results are as follows:（1）Using Te NWs as a template,polyacrylonitrile as a carbon and nitrogen source,and Te-PAN were prepared by electrospinning.After etching and carbonization,NRP-CNF is obtained.Conductivity,electrolyte contact area and sodium ion transport are greatly improved due to heteroatom doping and pores.Compared to nitrogen-free doped conventional graphite and nitrogen-doped non-porous fibers,the carbon material exhibits excellent cycle performance and rate performance(the rate capacity of 148 mA h g^-1 can still be achieved at a high current density of 10 A g^-1).（2）NiS₂NP/p-CNF were prepared by electrospinning and high temperature calcination.As an active material,NiS₂ is uniformly dispersed in carbon nanofibers,which can effectively reduce the problem of volume expansion.And the nitrogen-doped porous carbon nanofiber frame improves the conductivity of the electrode material,the sodium ion transport speed and the penetration of the electrolyte.The composite exhibits good cycle performance and rate performance.Our experimental results show that the porous fiber material prepared by electrospinning can be used as an anode material for sodium storage,and this method can also be extended to the preparation of other transition metal compounds.