Preparation And Lithium-/Sodium-Storage Performane Of Antimony-based Composites

With the development of human society and economy,the energy demand is gradually increasing and new energy storage technologies are booming.Lithium/sodium ion batteries have become one of the most promising energy storage and functional systems in the fields of intelligent electrical appliances,portable electrical appliances,electric vehicles,new energy development and utilization.With the rapid development of these fields,it is urgent to develop higher performance electrode materials to improve the performance of lithium/sodium ion batteries,so as to meet the increasing demand for performance.Antimony-based materials have become one of the most popular cathode materials systems for lithium/sodium ion batteries due to their unique advantages such as high theoretical specific capacity and good safety performance.However,in the process of charging and discharging,the antimony base anode will produce a large volume change,which will cause the structural integrity of the electrode material to be damaged,resulting in capacity attenuation and poor cycling performance,which will seriously affect its development and application.In order to improve the electrochemical lithium/sodium storage performance of antimony-base anode materials,a series of S-rGO/Sb₆O₁₃?CoSb_x/rGO@C?Sb₂S₃@C antimony-base composites were designed and prepared by means of solvent heat and high-temperature carbonization.In this paper,the physical and electrochemical properties as well as the structure-activity relationship were also studied,and the main content is as follows:1.Preparation of sulfur-doped reduced graphene oxide/Sb₆O₁₃ nanocomposite(S-rGO/Sb₆O₁₃)and their Lithium/Sodium Storage.Sb₆O₁₃/rGO nanocomposites were successfully with Sb₂O₃ as antimony source and graphene oxide?GO?by using solvothermal-low temperature vulcanization method.Then the S-rGO/Sb₆O₁₃nanocomposite was prepared by sulfurization treatment with sublimated sulfur as the sulfur source at low temperature.The influence of technological parameters such as temperature,time and sulfur doping amount on phase composition,structure and electrochemical lithium/sodium storage properties of the composite was investigated.The result shows:The S-rGO/Sb₆O₁₃ composite obtained by heat treatment at120?×12 h when the sulfur content addition amount is 30 wt.%has better lithium/sodium storage performance.When the lithium storage,the initial reversible specific capacity is 890.5 mAh g^-1 at a current density of 200 mA g^-1,with a initial Coulombic efficiency of 56.0%,the reversible capacity is 469.6 mA h g^-11 after 198cycles,52.7%capacity retention.When the sodium storage,the initial reversible specific capacity is 258.2 mAh g^-1 at a current density of 100 mA g^-1,an initial coulombic efficiency of 31.8%,the reversible capacity is 146.3 mA h g^-11 after 200cycles,56.6%capacity retention.2.Preparation of carbon-coated antimony-cobalt alloy/reduced graphene oxide nanocomposite and its lithium/sodium storage properties.CoSb_x/rGO@C composites was prepared by using solvothermal-calcination carbonization heat treatment method with Sb₂O₃,GO and Gum Arabic as raw materials.The influence of heat treatment temperature and carbon content on phase composition,structure and electrochemical lithium/sodium storage properties of the composite was investigated.The results show:That the CoSb_x/rGO@C nanocomposite prepared by annealing at 600?when the GA content is 20 wt.%,its exhibits distinguished cycling stability and rate capability.As the anode of a lithium-ion battery,the initial reversible specific capacity is 535 mAh g^-1 at a current density of 200 mA g^-1,an initial coulombic efficiency of 55.7%,the reversible capacity is 903 mA h g^-11 after 200 cycles;A reversible capacity of 489.3 mAh g^-1 is obtained after 500 cycles even at higher current rate of 500 mA g^-1 with excellent long-cycle performance,which is mainly attributed to the fact that the CoSb_x nanoparticles are completely coated in carbon,thus alleviating the volume expansion during charging and discharging improve the structural stability and integrity of the electrode.When the sodium storage,the initial reversible specific capacity is 134.5mAh g^-1 at a current density of 100 mA g^-1,an initial coulombic efficiency of 37.8%.3.Preparation of carbon-coated Sb₂S₃ nanocomposite and its electrochemical lithium/sodium storage properties.Sb₂S₃@C nanocomposites was successfully prepared by solvothermal-calcination carbonization method,using GA as carbon source,Sb₂O₃ as antimony source,and L-cysteine as sulfur sourcewith.The influence of carbon content on phase composition,structure and electrochemical lithium/sodium storage properties of the composite was investigated.The result shows:Sb₂S₃@C nanocomposite prepared at a GA content of 60 wt.%and a carbonization temperature of 600?×2 h has better lithium/sodium storage properties.As the anode material of a lithium-ion battery,the initial reversible specific capacity is 695.8 mAh g^-1 at a current density of 200 mA g^-1,an initial coulombic efficiency of 60.5%,the reversible capacity is 426.3 mA h g^-11 after200 cycles,61.2%capacity retention.The as Sb₂S₃@C nanocomposite is tried as the anode material for sodium ion battery,the initial reversible specific capacity is 210.5mAh g^-1 at a current density of 100 mA g^-1,an initial coulombic efficiency of 50.1%,the reversible capacity is 104.5 mA h g^-11 after 200 cycles.