The Preparation Of Two-dimensional Porous Antimony-based Sheet-like Nanocomposite And Its Sodium Storage Performance

As alternative batteries to lithium ion batteries,Sodium ion batteries have attracted extensive attention in the field of energy storage.The antimony-based active materials?including antimony and its compounds?are attracting extensive attention because of the high theoretical capacity and suitable potential as a novel anode materials for sodium-ion batteries.However,the poor conductivity and large volume changes during charging and discharging,which lead to poor cycling performance and is far from the commercial level for large-scale energy storage.The researchers proposed a series of strategies to solve the problems of the materials,such as carbon coated,nano-structure design and alloying can effectively alleviate the volume expansion of active materials during charging and discharging.The good electrical conductivity and mechanical properties of the carbon material,which can improve the conductivity of the material and effectively mitigate the volume change of the active material during charging and discharging;the novel nano-structure and morphology design,such as to reduce the size of the antimony-based active materials to nanoscale,so that shortening the distance of sodium-ion transport,improving the kinetic properties of the materials,or designing the special morphology,such as zero-dimensional spheres,one-dimensional rods,two-dimensional sheets,three-dimensional porous,which can effectively relieve volume changes during charging and discharging,and improve electrochemical performance of the materials.However,there are some problems the improvement process of materials of the reported researches.For example,the synthesis process is complex and costly,and the research method of the antimony cannot be used in other antimony-base compounds,and the morphologies of the materials are difficult to maintain in other compounds.Based on the above research present situation,this paper developed a simple,low cost,large-scale production of antimony compounds with carbon composites method,which prepared a series of unique two-dimensional?2D?porous "sheet on shteet"antimony-based with carbon composites,the morphology of the antimony and antimony-based active materials can be maintained;These 2D porous sheet nano-composites display the excellent electrochemical properties when used as negative electrode materials for sodium ion batteries?1?Using acetone and antimony acetate?Sb?Ac?₃?as the starting raw materials,a 2D porous hybrid nanosheets material?AC?with ultrathin Sb nanoplates?thickness 0.5nm?anchored on the acetone-derived graphene-like carbon porous nanosheets?Sb/AC?has been prepared through a facile and scalable route,i.e.an aldol reaction and subsequent calcination.Benefitting from the unique morphology and structure "sheet on shteet",the hybrid nanosheets exhibit superb electrochemical performances for sodium-ion storage.When cycled at 0.1 A g^-1,the 2D hybrid nanosheets electrode delivers a high initial charge capacity of 499 mA h g^-1 with a coulombic efficiency of 68.5%,and maintains a considerable charge capacity of 440 mAh g^-1 after 200 cycles?88.2%of capacity retention?.?2?Using the 2D Sb/AC hybrid nanosheets as the precursor,the part of Sb were oxided into Sb₂O₃ at a relatively low temperature in the air.The conductivity of Sb is better than Sb₂O₃,and the Sb₂O₃ can further alleviate the volume change of the Sb.Forming a multi-component of active material with carbon composite.At 0.1 A g^-1 current density,the capacity was maintained at 577 mA h g^-1 after 100 cycles.?3?Using the 2D Sb/AC hybrid nanosheets as the precursor,the Sb were oxided into Sb₂O₃ at a relatively low temperature in the air to form Sb₂O₃/AC composite,Sb₂O₃ could be converted into Sb₂S₃ by low temperature vulcanization to form Sb₂S₃/AC composite.At 0.1 A g^-1,the charge capacity of Sb₂S₃/AC was maintained at 567 mAh g^-1 after 100 cycles.?4?Using the porous 2D Sb/AC hybrid as the precursor was mixed with selenium powder at room temperature,and then transferred into a tubular furnace for rapid selenization at low temperature in N₂ atmosphere.Sb was transformed into Sb₂Se₃,and the Sb₂Se₃/AC composite was obtained.The characterization results showed that the 2D porous flake structure and morphology were well maintained in Sb₂Se₃/AC,showing satisfactory electrochemical properties.At a current density of 0.1 A g-after 100 cycles,the charge capacity of Sb₂Se₃/AC was maintained at 455 mA h g^-1.Similarly,the Sb₂Te₃/AC composite was prepared by low-temperature tellurization of Sb/AC with 2D porous precursor to convert Sb into Sb₂Te₃.The high reversible charge capacities of 488.9,444.8,391.4,and 310.7 mA h g^-1 were exhibited at current densities of 0.1,0.2,0.5,1,and 2 A g^-1.The charge capacity can recover to a high reversible capacity of 458.4 mA h g^-1 when the current density was reset back to 0.1 A g^-1,indicating excellent stability and reversible of the Sb₂Te₃/AC.