Application Of Sb-based Binary Metal Compounds As Anode Materials For Lithium/Sodium Ion Batteries

As the anode of lithium/sodium ion batteries,the ionic radius of sodium is much larger than that of lithium,so some anode materials of lithium ion batteries are not suitable for sodium ion batteries,such as commercial graphite materials.Therefore,choosing an appropriate anode material has become one of the important research directions of lithium/sodium ion battery.In the research,the performance of the existing anode materials is difficult to meet the battery requirements of high specific energy,high rate performance,and long cyclic stability at the same time.Among them,carbon materials have excellent cyclic stability,but their specific capacity is low.In addition,metal oxides and metal sulfides have a high theoretical capacity,but due to the relatively poor conductivity of the material and a certain volume expansion during cycling,it has poor cyclic stability and low rate capacity.In view of the above problems,antimony-based binary metal oxides/sulfides CrSbO₄,Mn₂Sb₂O₇,and MnSb₂S₄ with high specific capacity,and composites them with high-performance graphene materials are studied in this paper.It also provides new ideas for the design and construction of high-performance lithium/sodium ion battery electrode materials.And the transition metal M can react with the product to improve the reversible capacity and adapt to the volume change of the Li_x Sb/Na_xSb active during the insertion and extraction process.In addition,graphene is a two-dimensional?2D?carbon structure.And because of its extraordinary properties,including excellent electronic conductivity,great flexibility,excellent thermal properties and chemical stability,it has attracted widespread attention.The specific research work in this paper is as follows:CrSbO₄ and CrSbO₄ composite reduced graphene oxide?CrSbO₄/RGO?materials were synthesized by solid method and solvothermal method.And their physical and electrochemical properties as anodes for lithium ion batteries were studied.The results show that adding RGO to CrSbO₄ will improve the conductivity and electrochemical performance of battery.The discharge capacity of CrSbO₄/RGO reaches 443.64 mAh g^-1 after 100 cycles under the current density of 100 mA g^-1.In addition,there is still a rate capacity of 394.41 mAh g^-1 even at 600mA g^-1.Mn₂Sb₂O₇ and Mn₂Sb₂O₇ composite reduced graphene oxide?Mn₂Sb₂O₇/RGO?materials were prepared and studied for lithium ion battery anode for the first time.Furthermore,the electrochemical mechanism of Mn₂Sb₂O₇ was explored by ex-situ XRD,CV and TEM after cycling.The results show that the discharge capacity of Mn₂Sb₂O₇/RGO reaches 706.72 mAh g^-1 after 200 cycles under a current density of 200 mA g^-1.And the discharge capacity loss of each cycle of the Mn₂Sb₂O₇/RGO is only 0.096%,indicating that the Mn₂Sb₂O₇/RGO electrode has a good cyclic stability.MnSb₂S₄ and MnSb₂S₄ composite reduced graphene oxide?MnSb₂S₄/rGO?nanorod composites were successfully designed and synthesized.When used as a anode electrode of sodium ion battery,MnSb₂S₄/rGO nanorods have a discharge capacity of 665.25 mAh g^-1 after200 cycles at a current density of 200 mA g^-1,and a discharge capacity of 492.36 mAh g^-1 at2000 mA g^-1 after 700 cycles.These results indicate that the composite has excellent specific capacity and cyclic stability.Moreover,the reaction between MnSb₂S₄ and sodium ions was proved by CV and ex-situ XRD,and the electrochemical mechanism was further explored.