The Controlled Preparation And Electrochemical Energy Storage Properties Of Antimony-based Nanocomposites

Lithium ion battery is considered perfect energy storage system because of its high mass energy density,high operating voltage,long cycle life and little pollution and so on.But the uneven distribution of lithium resources and high cost become prominent along with the wider use of lithium ion battery,which restrict the further development of lithium ion battery.By contrast,sodium resources are more abundant,safer and cheaper.However,due to the limitation of the voltage of positive electrode materials,the working voltage and the mass energy density are generally low in the traditional sodium ion batteries.Therefore,people continue to develop new energy storage system with excellent performance and abundant resources.In recent years,the newly emerging sodium ion-based dual ion battery is one of them.Antimony-based materials show promising future for storing lithium(sodium),with the advantages of high theoretical capacity and suitable potential.However,when the lithium(sodium)is stored in metal-based materials,the volume of antimony-based materials will change and cycling performance will be poor at high current density,which limits its development in the field of large-scale energy storage.The specific research content is as follows:(1)To solve the problem of large volume variation for storing lithium and poor cycling performance at high current density,we design and fabricate watermelon-like yolk-hollow structure by in-situ formation of Sb nanoparticles inside carbon nanocages that are decorated on graphene sheets and distributed in N-doped amorphous carbon matrix with pyrolysis of GO sheets,SbCl3,citrate and cyanamide mixture.The obtained antimony/carbon/grapheme nanocomposite delivers an excellent reversible capacity of 592 mA h g-1 at 500 mA g-1 with a good cycling stability for 400 cycles.A high capacity of 413 mA h g-1 is retained even after 700 cycles at 1000 mA g-1.Therefore,effective design and optimization of electrode material structure is an important thought to improve the performance of electrode materials.(2)In order to explore high-performance antimony-based nanocomposite as the anode material of sodium ion-based dual ion battery,antimony/carbon/graphene nanocomposite with Sb nanoparticles inserting N-doped carbon matrix is successfully prepared by pyrolysis of GO sheets,SbCl3,citrate and cyanamide mixture and serves as an anode material for sodium ion-based dual ion battery.At the same time,commercial expanded graphite as the positive electrode,1 M NaClO4 EC/PC/DMC=2:1:1(v/v/v)as the electrolyte and the glass fiber as the separator are assembled into sodium ion-based dual ion battery.The sodium ion-based dual ion battery delivers an excellent reversible capacity of 73 mA h g-1 at 1000 mA g-1 with a good cycling stability for 1400 cycles and the CE is up to 98.3%after 1400 cycles.Meanwhile,at the current density of 200 mA g-1,the voltage of discharge is as high as 3.5 V.Reasonable structure of electrode materials is also applicable to improve the performance of sodium storage.