Preparations And Lithium-/Sodium-Storage Performance Of Antimony And Antimony Oxides Reduced Graphene Oxide Composites

With the development of society,the demand for high energy density lithium/sodium ion batteries become more and more urgent.The development of lithium/sodium ion batteries with high energy density has become a hot research topic in the world.Antimony and its oxides have high theoretical specific capacity and they are one of the most promising anode materials for lithium/sodium ion batteries.However,the large volume expansion during charging and discharging leads to poor electrochemical performance,which seriously hinders the practical use of such negative electrode materials.In order to effectively reduce the adverse effects caused by volume changes,and improve the electrochemical lithium/sodium properties of the antimony and antimony oxides-based anode materials,in this paper,graphene oxide is used as a carrier to recombine with antimony and its oxides to construct a micro/nano-structured Sb/r GO and Sb₆O₁₃/r GO composite.The conductive polymer was coated in situ to obtain Sb₆O₁₃/r GO@PANI.The composite materials can effectively reduce the volume effects and improve the electrochemical performance of the electrode material.Several conclusions can be obtained as following:1.Sb/r GO nanocomposites were successfully prepared by simple chemical reduction and annealing treatment using Sb₂O₃ and GO as raw materials.The effects of raw material ratio and annealing process on the composition,structure and electrochemical properties of the materials were investigated.As results,Sb/r GO nanocomposites with excellent lithium/sodium storage properties can be successfully obtained when the addition amount of 50 wt.%GO after being treated at 400°C for 3h:A reversible specific capacity of 372.0 m Ah g^-1 can be obtained,when used as an anode material for lithium ion batteries,and 390.9 m Ah g^-1 can be retained after 200cycles.After 800 cycles,there were still reversible capacity 210.3 m Ah g^-1 at a current density of 2000 m A g^-1.The reversible specific capacity of 300.8 m Ah g^-1 can be delievered as anode material for sodium ion batteries,which remains at 249.8 m Ah g^-1after 200 cycles.A reversible capacity of 182.6 m Ah g^-1 can be maintained at a current density of 500 m A g^-1 after 1000 cycles indicating,excellent electrochemical cycle stability and rate performance.2.Sb₆O₁₃/r GO nanocomposites with 3D structure were successfully prepared by solvothermal method using Sb₂O₃ and modified graphene oxide HGO as raw materials.The effects of raw material proportion,solvent heat treatment temperature,heat treatment temperature and time on material composition,structure and electrochemical properties were studied.The Sb₆O₁₃/r GO nanocomposite with 3D structure can be obtained,when addition of 25wt.%HGO and heat treatment at 140o C for 12 h.A high reversible specific capacity up to 956.1 m Ah g^-1 can be obtained,and 721.2 m Ah g^-1 can be remained after 200 cycles.In addition,the lithium storage mechanism of Sb₆O₁₃/r GO nanocomposites was investigated by ex situ TEM method and the reversible conversion-alloying reactions can be achieved during lithium storage:Sb₆O₁₃+26Li⁺+26e^-(?)6Sb+13Li₂O,Sb+3Li⁺+3e^-(?)Li₃Sb.3.Using aniline as monomer,Sb₆O₁₃/r GO@PANI nanocomposites were successfully prepared by insitu coating polyaniline(PANI)on the surface of Sb₆O₁₃/r GO nanocomposites,and the effect of polyaniline coating amount on the structure and electrochemical lithium storage performance of composites were investigated.When the PANI content is 2 wt.%,the obtained Sb₆O₁₃/r GO@PANI nanocomposite deliver a high first reversible specific capacity of 658.1 m Ah g^-1,and remains at 559.1 m Ah g^-1 after 200 cycles,corresponding to the capacity retention rate of 85.0%.