Design Preparation And Performance Study Of Sodium Ion Battery Anode Based On Iron Oxide/Graphene Composite Nanostructure

In recent years,with the rapid development of digital,communication,transportation and other industries,the dependence on lithium-ion batteries has increased,which leads to the shortage of lithium resources and serious restrictions on large-scale energy storage.Therefore,it is particularly urgent to develop and utilize the next generation of energy storage pools that can replace lithium-ion batteries.Sodium ion battery?SIB?is considered to be the most promising energy storage battery to replace lithium-ion battery because of its abundant resources,low price and similar energy storage mechanism.Unfortunately,due to the large radius of sodium ion,the application of sodium ion battery is limited.Therefore,it is very important to develop SIBs anode materials with excellent electrochemical performance.Based on these analyses,Fe₂O₃ with high specific capacity(1007 m Ah g^-1),low price,nontoxic and pollution-free has great potential as a negative material of sodium ion.However,during the charging and discharging process,the volume of Fe₂O₃ will change greatly,which makes the structure collapse and the capacity decay rapidly,leading to the decrease of cycle stability.The low electrical conductivity makes the reaction of the material blocked under high current,which leads to the unsatisfactory rate performance.In this paper,Fe₂O₃/N-doped graphene?Fe₂O₃/NG?composite nanomaterials were prepared by solvothermal method.Large specific surface area and high conductivity of graphene were used to improve the volume expansion and poor conductivity of Fe₂O₃.The porous Fe₂O₃/Fe₃O₄/nitrogen doped graphene?Fe₂O₃/Fe₃O₄/NG?composite nanomaterials were obtained by microwave treatment.After microwave treatment,the high conductivity Fe₃O₄ can improve the electron transport rate of the composite,and the voids and grain boundaries formed at the same time contribute to the diffusion of sodium ions in the Fe₂O₃/Fe₃O₄ heterojunction.By increasing the content of Fe-O-C bond,the structural stability of the composite is enhanced and more channels are provided for electron transport.Therefore,Fe₂O₃/Fe₃O₄/NG composite shows excellent sodium storage performance.When it's an anode material for SIBs,the Fe₂O₃/Fe₃O₄/NG composite provides specific capacity 363 m Ah g^-1 at100 m A g^-1On the other hand,in order to avoid the influence of binder on the performance of batteries in traditional coating methods,Fe₂O₃/three-dimensional nitrogen doped graphene?Fe₂O₃/3DNG?electrode materials without binder were prepared by chemical reduction method.Among them,the porous structure of three-dimensional graphene promotes the infiltration of electrolyte and alleviates the volume expansion of Fe₂O₃.At the same time,the high conductivity improves the electronic conductivity of the binder free composite.In addition,nitrogen doping can enhance the binding force between Fe₂O₃ and graphene and form smaller Fe₂O₃ nanoparticles,which promotes the rapid transfer of electrons and ions.The Fe₂O₃/3DNG electrode contributes to a high reversible capacity of 510 m A h g^-1 at 100 m A g^-1.