锂离子电池负极材料Li4Ti5O12的研究.pdf

锂离子电池负极材料Li4Ti5012的研究重庆大学硕士学位论文(学术学位) 学生姓名:赵文莉指导教师:朱伟副教授专业:化学学科门类:理学重庆大学化学化工学院二O一二:年四月㈣删 Res earch on Li4Ti5012 asthe Negative M aterials forLithium Ion Batteries AThesis Submitted toChongqing University inParti11Fulfillment oftheRequirement forthe Master’SDegree ofScience By Zhao胁nli Supervised by Sllecialty:Chemistry v _ College cfChemistry&Chemical Engineering of Chong qingUniversity,Chongqing,China April,2012 重庆大学硕士学位论文中文摘要摘要锂离子电池负极材料尖晶石型钛酸锂因为其“零应变扎|生而具有很好的发展前景,其理论比容量岁7 175mAh/g,(+/Li),此材料离子和电子电导率低(10一S/crr),制约了商品化应用。本文采用高温固相法制备钛酸锂, 并对样品进行了XRD、激光粒度分析表征,以及恒流充放电、循环伏安电化学性能测试。对固相法制备Lj4Ti5012材料工艺条件进行优化,实验表明,以金红石型TiO, 和Li2C03为原料,无水乙醇做分散剂,球磨混合均匀,在马弗炉中空气气氛下, 温度为800。C,煅烧1:2小时后合成的Li4Ti5012具有平稳的充放电电压平台和较高的放电比容量。对钛酸锂分别进行了大比例的金属掺杂(A1、Mg、Cr、Mn),结果表明大比例的金属掺杂后的材料比容量都降低,金属(A1、Mg、Cr)加入后材料充放电平台电压变化不大,掺杂金属Mn使得材料的充放电平台电压发生较大变化。以尿素为氮源对Li4Ti5012进行掺杂,提高其导电性能,结果表明加入尿素后的Li4Tis012样品仍然;丢有尖晶石结构,首次放电比容量有所升高,循环性能增强。以葡萄糖为碳源对Li4Tis012进行碳包覆研究,结果表明葡萄糖的加入量为 20%制得的Li4Ti5012/(:材料表现出很好的电化学性能,,1C倍率下充放电时材料的循环性能稳定。关键词:锂离子电池,Li4Ti5012,高温固相法,碳包覆重庆大学硕士学位论 ABSTRACT Spinel Li4Tis012 isi)romising anode material forrechargeable lithium ionbatteries due toits“zero。strain”.Itshigh reversible capacity is75mAh/g,and has adischarge platform of 5V relative to lithium the low ionic and electronic conductivity(10叫S/crr.)restricts was prepared by high temperature structure andparticle sizedistribution ofthe sample were tvestigated by XRD,laser particle . electrochemical propert ieswere analyzed through CV andcharge—discharge The preparation 0 Li4Ti5012 by solid state method was resuIts showed that Li4Ti50 2synthesized with rutileTi02 and Li2C03 at800。C,12h,ball milling hadstableplatfi’rmvoltageandhighdischarge apacity. Lithium titanatew￡Sdoped with alargeproportion ofmetal(A1、Mg、Cr、Mn). allofthedopedsample showed platform voltage ofthes