Study On Electrochemical Performance Regulation And Sodium Storage Mechanism Of Antimony Based Anode Materials For Sodium Ion Batteries

Antimony has higher sodium storage capacity and lower sodium embedding potential.It is a promising cathode material for sodium ion batteries.However,in the process of charge and discharge,the metal antimony negative electrode material realizes the storage of sodium through reversible alloying and dealloying reaction.The strong volume expansion induces the rapid capacity attenuation of the metal antimony negative electrode material and poor cycle stability.In order to solve the problem of the volume change of metal antimony negative electrode,this paper uses the strategies of carbon composite,coating and transition metal composite to inhibit the volume change of antimony and improve the cycle stability of antimony based negative electrode materials.The specific research contents include:（1）Antimony nanoparticles were synthesized by liquid-phase reduction method with glucose as carbon source,and then the metal was prepared by low-temperature calcination Sb@C compound material.XRD and SEM were used to characterize the morphology and structure of the samples Sb@C under the test condition of current density of 100 m A g^-1,the initial capacity of micro nanocomposites is 378 m Ah g^-1,and the capacity after 100cycle is 376 m Ah g^-1,and the corresponding capacity retention is as high as 99.8%.（2）In order to obtain antimony based negative electrode materials with high capacity and good cycling performance,Sb/HC composite materials were synthesized by mechanical ball milling with bagasse derived hard carbon and metal antimony as raw materials according to different mass ratios.The electrochemical performance test results show that the Sb/HC composite negative electrode material with mass ratio of 6:4 shows the best sodium storage performance.At 100 m A g^-1current density,the first charging capacity is 481.5m Ah g^-1,The first coulomb efficiency was 79.8%.After 100 cycles,the specific capacity remained 474 m Ah g^-1,and the capacity preservation rate was as high as98.44%.Its excellent sodium storage performance is attributed to the stable structure and excellent conductivity of hard carbon materials.（3）Finally,TM/Sb（TM=Fe、Co、Ni、Cu、Zn、Mn）composite negative electrode material was synthesized by liquid-phase chemical reduction method with SbCl₃as antimony source,transition metal chloride as transition metal source and sodium borohydride as reducing agent.The results of material structure characterization and electrochemical test show that the Fe/Sb composite negative electrode material shows the best sodium storage performance.At 100 m A g^-1current density,the maximum specific capacity of the Fe/Sb composite negative electrode material with mass ratio of 2:8 is 542.7m Ah g^-1.After 150 cycles,the capacity retention rate is 94.1%.