一维铌酸钾纳米材料的合成及其储锂性能
本文选题:纳米材料 + 锂离子电池 ; 参考:《宁波大学》2017年硕士论文
【摘要】:本论文首次以静电纺丝法合成了KNb_3O_8、K_(5.75)Nb_(10.85)O_(30)和K_2Nb_6O_(16)的一维铌酸钾纳米材料,并首次探索了这三种物质的储锂性能。本文分为五章。第1章,简要指出了本文的研究背景与选题意义,并重点介绍了纳米材料特别是一维纳米材料的特性、应用和主要制备方法。最后概述了论文的选题意义。第2章,以草酸铌,草酸和乙酸钾为主要原料,采用了静电纺丝法结合煅烧工艺合成了团聚严重的KNb_3O_8纳米棒。该KNb_3O_8为不是很稳定的类四边形结构,含有两种铌离子。KNb_3O_8用作电极材料时有一定储锂性能,但是其性能较差。在循环性能测试中,KNb_3O_8纳米棒首周的充电比容量为156.5 mAh g-1,第50周的充电比容量为65.6 mAh g-1。前50周的充电比容量保持率仅为41.9%。第3章,以草酸铌,草酸和乙酸钾为主要原料,采用了静电纺丝法结合煅烧工艺合成了分散的K_(5.75)Nb_(10.85)O_(30)纳米棒。该K_(5.75)Nb_(10.85)O_(30)为不太稳定的类四边形结构,只有一种铌离子。用作锂离子电池电极材料时,K_(5.75)Nb_(10.85)O_(30)纳米棒有良好的的倍率性能和循环性能。在倍率性能测试中,样品在第1周、第11周、第21周、第31周、第41周的充电比容量分别是153.2、107.4、81.7、64.7、113.7 mAh g-1。在循环性能测试中,K_(5.75)Nb_(10.85)O_(30)的前15周的充电比容量衰减较快,之后趋于稳定。K_(5.75)Nb_(10.85)O_(30)纳米材料从第15周到第90周的充电比容量的单周平均衰减率仅为0.2%。第4章,以草酸铌,草酸和乙酸钾为主要原料,采用了静电纺丝法结合煅烧工艺合成了分散的K_2Nb_6O_(16)棒。该K_2Nb_6O_(16)的结构主要是比较稳定的五边形结构,且只有一种铌离子。研究结果表明,K_2Nb_6O_(16)纳米材料具有优异的倍率性能和循环性能。在倍率性能测试中,K_(5.75)Nb_(10.85)O_(30)在第1周、第11周、第21周、第31周、第41周的充电比容量分别是94.3、80.5、61.1、43.6、88.7 mAh g-1。在循环性能测试中,第1周的充电比容量为94.8 mAh g-1,第90周的充电比容量为65.7 mAh g-1。第1周到第90周的充电比容量的单周平均衰减率仅为0.8%。第5章,简单总结了本论文的工作并展望了课题可能的发展。
[Abstract]:In this paper, the one-dimensional potassium niobate nanomaterials of KNb3OS _ 8K _ S _ (5.75) and K _ 2Nb _ (6) O _ (16) have been synthesized by electrospinning for the first time, and the lithium storage properties of these three substances have been explored for the first time. This paper is divided into five chapters. In chapter 1, the research background and significance of this paper are briefly pointed out, and the characteristics, applications and main preparation methods of nanomaterials, especially one-dimensional nanomaterials, are emphatically introduced. Finally, the significance of the thesis is summarized. In chapter 2, KNb_3O_8 nanorods with severe agglomeration were synthesized by using niobium oxalate, oxalic acid and potassium acetate as main raw materials. The KNb_3O_8 is an unstable quadrilateral structure and contains two kinds of niobium ions. KNbSZ _ 3O _ (8) has some lithium storage properties when it is used as electrode material, but its performance is poor. In the cycle performance test, the charge specific capacity of the KNbS _ 3O _ 8 nanorods was 156.5 mAh g ~ (-1) in the first week and 65.6 mAh g ~ (-1) in the 50 ~ (th) week. The charge specific capacity retention rate for the first 50 weeks was only 41.9. In chapter 3, using niobium oxalate, oxalic acid and potassium acetate as the main raw materials, the dispersed K _ S _ (5.75) NbS _ (10.85) O _ (30) nanorods were synthesized by electrospinning method and calcination process. The Kill 5.75 NbSch 10.85 O\ + _ (30) is an unstable quadrilateral structure with only one niobium ion. When used as electrode material for lithium-ion battery, the nanorods have good rate performance and cycling performance. In the rate performance test, the charge specific capacity of the sample at week 1, week 11, week 21, week 31 and week 41 is 153.2107.4 渭 m, 64.7113.7 mAh g-1, respectively. In the cycle performance test, the charge specific capacity of Kstack 5.75 / NbSerp 10.85 / O / C) decreased rapidly in the first 15 weeks and then tended to be stable. The average attenuation rate of charge specific capacity of the nanomaterials from the 15th to the 90th week was only 0.2k.Then, the average attenuation rate of the charge specific capacity of the nanomaterials from the 15th week to the 90th week was only 0.22%. In chapter 4, using niobium oxalate, oxalic acid and potassium acetate as main raw materials, the dispersed K _ 2NbS _ 6O _ (16) rod was synthesized by electrospinning method and calcination process. The structure of the K2Nb6O _ (16) is mainly a relatively stable pentagonal structure, and there is only one niobium ion. The results show that the nanocomposites have excellent rate performance and cycle performance. In the rate performance test, the specific charge capacity of mAh in the first week, the 11th week, the 21st week, the 31st week, and the 41st week were 94.3 / 80.5 / 61.1 / 43.6/ mAh / g ~ (-1), respectively, and the specific charge capacity was 10.85 mAh / g ~ (30) in the first week, the 11th week, the 21st week, the 31 th week, the 41 th week, respectively. In the cycle performance test, the charging specific capacity was 94.8 mAh g-1 in the first week and 65.7 mAh g-1 in the 90th week. The average weekly attenuation rate of the charge specific capacity from week 1 to week 90 is only 0.8. In chapter 5, the work of this thesis is summarized and the possible development of this thesis is prospected.
【学位授予单位】:宁波大学
【学位级别】:硕士
【学位授予年份】:2017
【分类号】:TQ340.64;TB383.1
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