锂离子电池负极材料二氧化锡的合成与其改性-研究

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1、摘要2+羧基化、开端的OCNTs，再借助毛细管作用和表面张力作用将Sn引入碳纳米管的空腔内，自氧化后得到SnO2纳米粒子（4-6nm）。XRD，SEM，TEM等物理表征手段都指出SnO2纳米颗粒大部分填充于OCNTs内。电化学性能分析表-1明，此复合物能明显改善SnO2的循环稳定性，首次放电比容量为848mAhg，-1在70mAg电流密度下循环300次后容量保持率高达83.5%。甚至在3000mA-1-1g下材料仍保持了398mAhg的放电比容量。这些优异的电化学性能绝大部分+取决于SnO2@OCNTs复合物的结构优势：（1）SnO2纳米粒子能缩短Li的扩散距离；（2）OCNTs能提高了复合

2、材料导电性能；（3）OCNTs上生长的SnO2纳米粒子分散均匀，能抑制原位生成的Sn粒子的团聚；（4）SnO2填充在OCNTs管内，OCNTs作为缓冲层，能缓解在循环时SnO2剧烈的体积变化。关键词：SnO2、锂离子电池、CNTs、模板法、湿化学法II万方数据ABSTRACTABSTRACTLithium-ionbatterywasregardedasoneofpromisingenergystoragedevices+rencently.Theperformanceoflithium-ionbatterieslargelydependsonListoragecapacitiesofacti

3、vematerialelectrode.Improvementsinelectrodematerialscouldmotivateeffortstomakingthestructuremoreflexibilityandstability,improvingthe+revesiblecapacity,makingmuchsaferandLiinsertion-removalstagingelectrochemicalprocessfacile.Todate,graphitehasbeenwidelyusedasthecommerciallydominantanodematerialinlit

4、hium-ionbatteriesduetoitslowcost,highyield,negligiblevolumeexpansion(9%)oncyclingandexcellentcapacity-1retention.Butthetheoreticalspecificcapacityofgraphitewaslimitedto372mAhgandgraphitesufferedsafetyissues.Tinoxide(SnO2)couldbeproposedasoneofpromisingsubstitutesforthegraphiteanodeowingtoitshighthe

5、oreticalspecific-1lithiumstoragecapacityof781mAhgandlowpotentialoflithiumionintercalation.However,thepracticalapplicationofSnO2hasbeenrestrainedbyitscyclingperformance.Thelargevolumechange(about300%)andsevereagglomerationduringthechargeanddischargeprocessesleadtoelectrodepulverizationandelectricald

6、isconnection,resultinginlimitationofcyclelife.Manyattemptshavemitigatedtheselimitations.Inthispaper,twokindsofeffectivemethods,includingoptimizingthemorphologyofSnO2andmakingSnO2-basedcomposites,wereusedtomodifySnO2.Theelectrochemicalperformancesoftwomaterialsasanodeelectrodeswerealsostudied.Thecon

7、clusioncanbesummarizedasfollowing:1.Wereportaneffectivetemplatingmethodologytopreparecorrugate-likeSnO2byusingcellulosicsubstances(cottonfibers)assacrificingtemplate.SnCl2wasusedasprecursor.Cottonfibersnatu