碳复合锡基纳米材料的制备及其在锂离子电池负极材料中的应用

发布时间：2018-03-10 03:08

本文选题：锂离子电池　切入点：负极材料　出处：《南京师范大学》2014年硕士论文　论文类型：学位论文

【摘要】：近几年来,已经商业化的锂离子电池负极材料一般是石墨以及各种碳材料。但是随着便携式电子设备、电动汽车和储能装置的高速发展,碳基材料低的比容量已经不能满足其要求,因此,迫切需要寻求具有高比容量的新型负极材料。锡基材料具有高的体积和质量比容量,被认为在高能量密度和高功率密度锂离子动力电池中具有良好的潜在应用前景。然而,锡基材料在充放电过程中存在着体积膨胀问题,这会导致电极材料的粉化、失去电接触以及容量的快速衰减。碳复合的锡基材料具有纳米材料和碳复合的优势,有望满足锂离子动力电池的需求。本论文以锡基负极材料为研究内容,包括二硫化锡(SnS2)、二氧化锡(Sn02)和锡基合金。以三维介孔碳为载体、Sn纳米球和SnCl4/K2Ni(CN)4氰胶为前驱体,通过简便的化学反应制备了一系列碳复合的锡基纳米材料。由于独特的结构和组成特性,这些锡基复合纳米材料均表现出了较好的储锂性能。本论文的主要创新结果如下： (1)以三维介孔碳为载体,通过简便的液相化学反应制备出介孔碳负载的SnS2纳米片。与纯的SnS2相比,介孔碳负载SnS2纳米片结合了SnS2的二维层状结构和介孔碳的三维多孔结构的优势,因而表现出了较好的容量保持率、较高的比容量和倍率特性。例如,在100mA·g-1的充放电速率下经过50次循环,介孔碳负载SnS2纳米片的放电比容量保持在428.8mAh·g-1,远高于纯的SnS2负极材料在50次循环之后的比容量(282.2mAh·g-1)。 (2)以Sn纳米球为前驱体,通过Si02包覆、热处理、碳包覆以及最后的去除Si02过程制备得到Sn02@C蛋黄-蛋壳结构纳米球。与纯的Sn02纳米球相比,Sn02@C蛋黄-蛋壳结构纳米球表现出了较好的容量保持率、较高的比容量和倍率特性。例如,在100mA·g-1的充放电速率下经过30次循环,Sn02@C蛋黄-蛋壳结构纳米球的放电比容量保持在515.2mAh·g-1;而在500mA·g-1和1A·g-1的高充放电速率下,其放电比容量仍分别高达395.8(?)307.5mAh·g-1。 (3)以SnCl4/K2Ni(CN)4氰胶为前驱体,通过简便的液相还原过程及随后的葡萄糖水热碳化过程制备得到三维多孔Sn-Ni@C复合纳米材料。由于独特的结构和组成特性,三维纳米多孔Sn-Ni@C复合材料表现出了优越的循环性能、高的比容量和倍率特性。例如,在200mA·g-1的充放电速率下经过40次循环,其放电比容量不再衰减,保持在440.0mAh·g-1。
[Abstract]:In recent years, cathode materials for lithium ion batteries that have been commercialized have generally been graphite and various carbon materials. But with the rapid development of portable electronic devices, electric vehicles and energy storage devices, The low specific capacity of carbon-based materials can not meet its requirements. Therefore, it is urgent to seek new negative electrode materials with high specific capacity, and tin based materials have high volume and mass specific capacity. It is considered that there are good potential applications in high energy density and high power density lithium-ion power batteries. However, the bulk expansion of tin based materials in charge and discharge process, which will lead to the electrode material powder. Due to the loss of electrical contact and the rapid attenuation of capacity, the carbon composite tin based material has the advantages of nano-material and carbon composite, which is expected to meet the needs of lithium-ion power battery. In this thesis, tin based anode materials, including tin disulfide SNS _ 2, Sn _ 2O _ 2, Sn _ 2O _ 2 and tin based alloys, were used as materials, and three dimensional mesoporous carbon as carrier, Sn nanospheres and SnCl4/K2Ni(CN)4 cyanide were used as precursors. A series of carbon composite tin based nanomaterials have been prepared by simple chemical reaction. Due to their unique structure and composition properties, these tin based composite nanomaterials have good lithium storage properties. The main innovative results of this thesis are as follows:. 1) SnS2 nanoparticles supported on mesoporous carbon were prepared by a simple liquid phase reaction using three-dimensional mesoporous carbon as the carrier. The mesoporous carbon supported SnS2 nanochips combine the advantages of the two-dimensional layered structure of SnS2 and the three-dimensional porous structure of mesoporous carbon, thus showing better capacity retention, higher specific capacity and ratio characteristics. After 50 cycles at the charge / discharge rate of 100mA 路g ~ (-1), the specific discharge capacity of mesoporous carbon supported SnS2 nanoparticles remained at 428.8 mAh 路g ~ (-1), which was much higher than that of pure SnS2 anode material after 50 cycles (282.2 mAh 路g ~ (-1)). Using Sn nanospheres as precursor, Si02 coating, heat treatment, Sn02@C yolk-eggshell structure nanospheres were prepared by carbon coating and final Si02 removal process. Compared with pure Sn02 nanospheres, Sn02C yolk-shell structure nanospheres showed better capacity retention, higher specific capacity and higher specific capacity and ratio properties, for example, compared with pure Sn02 nanospheres, Sn02C yolk-shell structure nanospheres showed better capacity retention, higher specific capacity and higher specific capacity than pure Sn02 nanospheres. At the charge / discharge rate of 100mA 路g-1, the discharge specific capacity of Sn02C yolk-shell structure nanospheres remained at 515.2 mAh 路g-1 after 30 cycles, but at the high charge-discharge rate of 500mA 路g-1 and 1A 路g-1, the discharge specific capacity was still as high as 395.8? 307.5mAh 路g-1. Three dimensional porous Sn-Ni@C composite nanomaterials were prepared by simple liquid phase reduction and subsequent hydrothermal carbonization of glucose using SnCl4/K2Ni(CN)4 cyanide gel as precursor. Three-dimensional nano-porous Sn-Ni@C composites exhibit excellent cycling performance, high specific capacity and rate characteristics. For example, after 40 cycles at a charge / discharge rate of 200mA 路g ~ (-1), the specific discharge capacity of the composite is no longer attenuated and maintained at 440.0 mAh 路g-1.
【学位授予单位】：南京师范大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TB383.1;TM912

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