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Electrospinning Preparation And Research Of SnO2/C Matrix Composites

Posted on:2021-02-06Degree:MasterType:Thesis
Country:ChinaCandidate:J Y SunFull Text:PDF
GTID:2381330614953624Subject:Chemistry
Abstract/Summary:PDF Full Text Request
With the popularization of portable electronic devices,vehicles and other products,the performance requirements of energy storage system have been further improved.In recent years,the national emphasis on new energy research has also promoted the development of energy storage systems.Lithium ion battery?LIB?as an energy storage equipment with the superiority of high energy density,strong security,and environmental friendly has been favored by researchers.The negative electrode material as one of the important components of LIB has also been widely studied.However,for the commonly used commercial anode material graphite,the low energy density and the safety problems caused by the low lithium insertion potential hinder the further development of LIB.People try to replace the commercial graphite anodes by looking for other materials,fusion doping,coating and other technologies to produce high-performance anode materials.Nanocomposite materials came into being.SnO2 nanofiber material has become one of the most potential lithium ion battery anode materials due to its large reversible capacity,ordered configuration and large specific surface area.However,its volume expansion and pulverization problems during the LIB cycle cannot be effectively solved.Doping and modifying tin dioxide nanofiber anode materials and constructing special morphological structures are considered to be effective methods for stabilizing electrodes.In this thesis,SnO2nanofibers are used as research objects,polyacrylonitrile?PAN?with high electrical conductivity and thermal stability is used as a stable carbon source,and electrospinning and heat treatment techniques are used to prepare SnO2 carbon nanofibers and Ge O2 doped SnO2 carbon nanoparticles.Fiber and use it as a negative electrode material for lithium ion batteries.The specific research work is as follows:?1?Using electrospinning technology to prepare SnO2/C nanofibers with PAN as a stable carbon source,using the same technology to prepare SnO2/C nanofibers doped with different polymers?polyvinylpyrrolidone/PVP,polymethyl methacrylate/PMMA?.After heat treatment,physical and chemical properties are characterized.The experimental results show that the PVP-doped SnO2/C nanofibers have the smallest specific surface area,strong cycle stability,and the capacity is 632.3m Ah/g at 50 m A/g after 50 cycles.?2?Based on the above processes,the effects of Ge O2 doped SnO2/C nanocomposites under different temperature conditions were explored.After some tabulations,it is concluded that the GSC nanocomposite at a carbonization temperature of 600? has better cycle stability and rate performance than the materials carbonized at 500? and 700?.?3?Under the premise of the above preparation of SnO2/C nanofibers with PAN/PVP as the carbon source,electrospinning technology was used to further prepare nano-Ge O2 doped SnO2/C nanofibers and apply them to lithium-ion batteries for performance Characterization.The results show that the SnO2/C nanocomposite material doped with nano-Ge O2 has a higher specific capacity and a larger specific surface area.The first discharge capacity is 1630.96 m Ah/g,the capacity after 50cycles is 787.01 m Ah/g,and the coulombic efficiency is 98.3%.It shows that the doping of Ge O2 effectively increases the specific discharge capacity of SnO2/C nanomaterials,reduces the resistance of the cycle process,increases the specific area,and enhances the cycle stability of the lithium-ion battery.The research of the composite material is expected to promote the further development of anode materials for lithium-ion batteries.
Keywords/Search Tags:Tin dioxide, Electrospinning, Lithium ion batteries, Anode materials
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