Preparation And Sodium Storage Properties Of High Performance Antimony-based Electrode Materials

Efficient energy storage and conversion is of great significance for creating a world with zero carbon emissions.In recent years,sodium ion batteries have been considered as a potential alternative to lithium ion batteries due to their similar electrochemical reaction mechanism,abundant resource reserves and low price.However,Na⁺has a large ionic radius,which leads to slow ion dynamics.Therefore,it is an urgent problem to explore and develop new high-performance anode materials for sodium ion batteries.Antimony-based composite materials have attracted the attention of researchers at home and abroad due to their high theoretical specific capacity and low cost.However,as a negative electrode material for sodium ion batteries,the volume of the electrode material is seriously expanded and pulverized during the charge and discharge process due to the removal/insertion of sodium,resulting in rapid capacity decay,which limits the development of antimony-based materials.In view of these problems,this paper will prepare antimony-based materials into new sodium ion battery anode materials with high performance,high rate and stable cycle through structural construction,carbon material modification and synthesis methods.The main research contents are as follows:1.Sb₂S₃/S@S doped carbon composites with hollow core-shell structure were successfully prepared by template method and complexation reaction.Through finite element simulation,dynamic analysis and density functional theory calculations,the role of S composites and hollow core-shell structures in improving performance was revealed.The internal S and external S-doped carbon can interact with Sb₂S₃ to improve the reactivity with Na⁺and effectively release the stress of Sb₂S₃ during the sodium process.This special structure makes it have high reversible capacity,good cycle performance and high rate performance.The assembled full cell also exhibits excellent energy density at high power,and maintains a high reversible capacity of 310 m Ah g^-1after 500 cycles at 1 A g^-1.2.Sb/Sb₂O₃@N,S-C/r GO with two-dimensional layered structure was prepared by template method and complexation reaction method as anode material,which achieved excellent sodium storage performance.The results show that the Sb-O-C in the interface can promote the electrochemical activity,significantly improve the electronic conductivity and enhance the ion transport.Secondly,the introduction of carbon matrix and in-situ formed metal Sb can also improve the structural stability and electronic conductivity of the material.Sb₂O₃ is sodiumized to form Na₂O,which buffers the volume change,thereby improving the cycle stability and rate performance of the material.In addition,N doping activates the storage sites in the carbon lattice,and S doping can improve the Na⁺adsorption capacity,thereby increasing the specific capacity,enhancing the structural stability of the material,and prolonging the cycle life.The assembled full cell also exhibits excellent energy density at high power,and can still have a high reversible capacity of 391 m Ah g^-1 after 200 cycles at 1 A g^-1.3.Mo-doped Sb₂S₃/r GO was prepared by hydrothermal method based on GO template and metal ion doping,which realized excellent sodium storage performance.The results show that Mo doping can effectively adjust the electronic structure of Sb₂S₃/r GO and optimize its electronic conductivity,charge transfer efficiency and structural stability.In the voltage range of 0.01-3.0 V,the 7%Mo-Sb₂S₃/r GO nanocomposite has good cycle stability and rate performance.After 100 cycles at a current density of 1 A g^-1,the specific capacity can reach 744 m Ah g^-1.Even at 20 A g^-1,the reversible capacity remains at 400 m Ah g^-1,equivalent to 42.2%of the capacity at 0.2 A g^-1.In addition,the 7%Mo-Sb₂S₃/r GO nanocomposite has a pseudocapacitance-controlled fast sodium insertion/extraction kinetics.