Controllable Construction Of Antimony-based Oxides On Carbon Cloth And Their Lithium/Sodium Storage Properties

Carbon cloth is widely used in flexible electrodes because of its high conductivity,porous network structure,large specific surface area,good mechanical flexibility and strength.At present,antimony-based oxides have shown potential as active substances,which can be used as anodes in both lithium-and sodium-ion batteries.If these materials can be successfully applied to the surface of carbon cloth,it is expected to achieve high electrochemical energy storage performance on the surface of flexible matrix materials,which can further expand the application potential of these materials.However,their controllable preparation on carbon cloth has been challenging.Moreover,the regulation of their morphology and structure,the relationship between their structures and properties and the mechanism of performance improvement are not clear.Based on this,the controllable preparation of various antimony oxides（i.e.Sb₂O₃,Sb₂O₄ and Sb₂O₅）on carbon cloth are realised in a liquid environment.The energy storage and mechanism of the antimony oxides are explored in order to establish the theoretical and structural basis for their application in antimony-based oxide/carbon cloth.The resulting antimony-based oxide/carbon cloth is used as anode in lithium-and sodium-ion batteries.The specific and innovative achievements are described below.（1）Using surface anodizing technology,the structure of polar functional groups on the surface of carbon cloth is regulated,which constructs the basis of surface structure for the uniform and controllable growth of antimony-based oxides.Specifically,the control of C=O functional groups on the surface of carbon cloth was realised using a pre-activation treatment technology.The growth of Sb₂O₅ nanoparticles was used as an example.The results show that a sufficient amount of C=O functional groups is more conducive to the uniform growth of Sb₂O₅ and the formation of interfacial C-O-Sb bonds,thus realising the high electrochemical performance of the prepared Sb₂O₅ nanoparticles/carbon cloth electrode.At a current density of 200 mA g-1,a high specific capacity of 641 mAh g-1 can still be provided after 150 cycles.（2）The structural regulation of Sb₂O₃ was designed on a carbon cloth using a solvothermal reaction.Irregular polyhedron Sb₂O₃ and nanoparticle Sb₂O₃ were prepared on the carbon cloth,respectively.Their sodium storage properties and mechanism were investigated.The nanoparticle Sb₂O₃/carbon cloth showed a higher sodium storage capacity.This may be due to the smaller size of the nanoparticle Sb₂O₃,which hastens the electrochemical kinetics.This can stabilise the interface and accelerate the kinetics of the alloying reaction used.Therefore,the irregular polyhedron Sb₂O₃ is partially oxidised in the liquid environment.Additionally,the multi-level structure of irregular polyhedron Sb₂O₃ and Sb₂O₅ nanoparticles is realised on the surface of the carbon cloth.The resulting multi-level composite showed a high sodium storage capacity.（3）Due to the strict requirements for pH in the preparation of Sb₂O₃,the higher valence Sb₂O₄ was prepared and studied.By controlling the solvothermal reaction conditions,pure flower Sb₂O₄ with different sizes on carbon cloth were successfully prepared using spindle self-assembly.The flower Sb₂O₄ with length and width of-200 and 50 nm,respectively,in pure ethanol,showed a higher sodium storage capacity.At a current density of 0.5 A g-1,a high specific capacity of 314.8 mAh g-1 can still be provided after 500 cycles.This property is closely related to the morphology of the electrode and the stable C-Sb bond.The combination of C-Sb bonds between Sb₂O₄ and CC maintains the structural stability of the Sb₂O₄/CC electrode and accelerates the kinetic balance of both conversion and alloying reactions.（4）In order to stabilize the magnification and cycling performance of flower shaped Sb₂O₄,SiO2 nanoparticles were immobilised on the flower-like Sb₂O₄ surface to prepare SiO2/Sb₂O₄ double oxide as a self-supporting electrode material on carbon cloth.When the composite is used as the anode of lithiumand sodium-ion batteries,it showed a high area-specific capacity.When used as the anode of a lithium-ion battery,the discharge specific capacity values are 4.34,3.35,2.34 and 1.49 mAh cm-2 when the current density values are 0.1,0.2,1 and 2 A cm-2,respectively.The research mechanism study shows that the addition of SiO2 results in a Sb₂O₄/carbon cloth electrode with high reversibility in conversion and alloying.This is likely related to the highly stable solid electrolyte interface（SEI）film that was formed on the surface of the composite.（5）Due to the large structure size of Sb₂O₄,it has to face serious pulverization in the cycle.Therefore,the high valence Sb₂O₅ was prepared and studied.In the liquid environment used,the structure and morphology of Sb₂O₅ were regulated on the surface of the carbon cloth.When spherical Sb₂O₅/CC is used as the anode of a lithium-ion battery,the discharge area-specific capacity values are 4.1,4.0,3.7,3.2,2.6 and 1.7 mAh cm-2 when the current density values are 0.1,0.2,0.5,1,2 and 5 A g-1.However,the sodium-ion storage performance needs to be improved.Additionally,the polyhedral Sb₂O₅ is prepared on the surface of the carbon cloth.Due to its unique structure,prominent active sites for reaction with sodium ions are present.These shorten the contact distance and reduce the steric hindrance of its reaction with sodium ions,thus providing a high specific capacity.（6）In addition,in order to improve the cycle stability of spherical Sb₂O₅,SiO2/Sb₂O₅/CC composite was prepared using a one-step hydrothermal method.It showed a spiny sphere morphology,which was formed by the combination of Sb₂O₅ and SiO2.An additional mechanism study found that the stable energy storage mechanism of the SiO2/Sb₂O₅/CC electrode is likely due to the loading of SiO2 on the surface of Sb₂O₅.This reduces the SEI area formed by the electrolyte on the surface of Sb₂O₅,thereby avoiding the formation of a composite with a partially broken SEI film that is caused by the intercalation of the lithium and sodium ions in Sb₂O₅.This provides an important surface structure basis for Sb₂O₅ to show high electrochemical lithium/sodium storage performance,and also provides a new understan。ding for further understanding the evolution of charge discharge surface structure of this kind of materials.