Research On The Controllable Preparation, Electrochemical Performance And Gas Sensitivity Of Tin Dioxide-based Metal Oxide Micro-nano Structure

Metal oxide micro-nano structure has unique physical and chemical properties,and has a wide range of applications in lithium-ion batteries,sensors,catalysts and other fields.As an anode material of lithium-ion battery,metal oxide has the advantages of high theoretical specific capacity,environmental friendliness and rich resources.However,in the process of charging and discharging,the volume expansion of metal oxides is serious,and the cycle stability is poor.As a gas sensing material,metal oxide has the advantages of high sensitivity and low price,but its working temperature is high and its selectivity is poor.In view of the above problems,this work takes the tin dioxide based micro-nano structure as the research object,designs and prepares metal oxide composite materials with excellent electrochemical performance and gas sensing performance,and deeply explores the influence of the material microstructure on the performance.The main research contents are as follows:?1?For the first time,a novel SnO₂@?-Fe₂O₃ hollow micro-nano structure was prepared by simple hard template method and hydrothermal method.Firstly,SnO₂ hollow spheres were prepared by hard template method,and then SnO₂@?-Fe₂O₃ hollow micro-nano structure was obtained by hydrothermal method.The defects such as oxygen vacancies and dislocations in SnO₂@?-Fe₂O₃ hollow micro-nano structure were studied.The effect of NaOH etching temperature on the morphology of SnO₂ hollow spheres was investigated.?2?Compared with SiO₂@SnO₂ and SnO₂,SnO₂@?-Fe₂O₃ sample has higher reversible specific capacity and better cycle stability.The high specific capacity of SnO₂@?-Fe₂O₃ hollow micro-nano structure was maintained at 1043 mAh g^-1 for 190cycles at 100 mA g^-1.Using transmission electron microscopy to characterize the anode material after cycling,it was found that SnO₂@?-Fe₂O₃ has high structural stability.The high lithium storage capacity and excellent cycle stability are attributed to the unique hollow urchin structure,heterojunction interface and oxygen vacancy.The novel hollow urchin like structure can effectively inhibit the agglomeration of materials,alleviate the volume expansion,and improve the electrochemical cycle stability.?3?It is found that SnO₂@?-Fe₂O₃ hollow micro-nano structure has better gas sensing performance than SiO₂@SnO₂ and SnO₂.It is found that SnO₂@?-Fe₂O₃ sample has the advantages of low operating temperature,high sensitivity and good selectivity.SnO₂@?-Fe₂O₃ sample shows excellent gas sensing performance.On the one hand,the larger specific surface area provides more surface active sites.On the other hand,the heterojunction structure will promote the electron flow and improve the gas sensing performance.