Ionic Liquid-assisted Preparation Of Anode Materials For Sodium-ion Batteries

At present,lithium ion battery has been commercialized and applied in many fields.With the rapid development of society,the demand for lithium-ion batteries is increasing.However the distribution of lithium resources on earth is not uniform,and the price of lithium is rising,leading to the high cost of the lithium ion battery.Sodium ion batteries are attracting great attention due to its similar properties with Li and the rich resources.But the radius of sodium ion is greater than that of lithium ion,so that some anode materials used in lithium ion battery can not be applied to sodium ion battery.Therefore we need to find a suitable electrode material for sodium ion battery.One of the reasons for sodium ion battery can not be commercial is that the anode material can not provide good cycling stability and high rate performance.As a result,the preparation of suitable anode materials is particularly important for the development of sodium ion batteries.Na alloy-based anodes,which can provide much higher gravimetric and volumetric specific capacities,are attracting intensively attentions these years.Among them,antimony（Sb）、tin（Sn）and Sb-based、Sn-based materials are regarded as promising anodes due to their large theoretical capacity.However,the commonly used synthesis methods suffer from some disadvantages such as tedious procedure,harsh reaction conditions.Room temperature ionic liquids with low melting point,wide liquid temperature range,thermal stability and chemical stability etc.,is a kind of green solvent.In recent years,it has received extensive attention on the preparation of inorganic nanomaterial.Based on that,we fabricated Sb2S3/rGO and SnO2/N-rGO nanocomposite by ionic liquid assisted hydrothermal method and research their application in Sodium ion batteries.The main research contents are as follows:（1）Ionic Liquid-Assisted Preparation of Sb2S3/reduced Graphene Oxide Nanocomposite for Sodium-Ion BatteriesHerein,we proposed a facile approach to fabricate Sb2S3/rGO nanocomposite by ionic liquid assisted hydrothermal method.The obtained IL-Sb₂S₃/rGO nanomaterial exhibits a high capacity of 687.7 mA h g^-1 at 50 mA g^-1,good cycling stability and an excellent rate performance(400 mA h g^-1 after 100 cycles at a current density of 500 mA g^-1)when being used as anode in SIB.The promising electrochemical properties can be attributed to the uniformly distribution of Sb₂S₃ on rGO layers and the close contact between the two composites,which can be ensured by the addition of ionic liquid during the synthesizing process.（2）Ionic Liquid-Assisted Preparation of SnO₂/N-Reduced Graphene Oxide Nanocomposite for high capacity Sodium-Ion half and full BatteriesHere,a SnO₂/N-rGO nanocomposite fabricated by a facial hydrothermal method utilizing ionic liquid[BMIM]N（CN）₂ as auxiliary solvents and the nitrogen sources is reported in this work.The obtained anode exhibits a high capacity of 607.6 mA h g^-1,an outstanding rate performance of 261.8 mA h g^-1 at 2 A g^-1 and a stable cycle performance in Na⁺half cell.Also,the composite expressed a better rate performance that a capacity of 133.3mA h g^-11 at a high current density of 2.4 A g^-1 was obtained and a relative cycling performance that retaining 156.8 mA h g^-1 with 74.3%of the initial capacity at 0.3 A g^-1 after50 cycle in Na⁺full cell.The impressive Na storage performance was mainly attributed to the doping of N atom into reduced graphene oxide resulting in the better conductivty and the uniform distribution of the SnO₂ on N-rGO.