论文总字数：23088字

摘 要

单质硫作为二次锂-硫电池正极时具有很高的理论比容量（1675mAh/g）,此外硫原料廉价、储量丰富、对环境友好，被认为是最具发展潜力的新一代高比能化学电源的正极材料之一。但由于单质硫存在导电性差以及充放电过程中体积膨胀，放电过程中产生的多硫离子会溶解发生扩散迁移，从而制约了锂-硫电池的进一步发展应用。^[1]为了克服这些困难，本文中通过查阅大量文献和相关资料，采取石墨烯和硫复合的方法改善材料性能。先通过改进的Hummer法制备出氧化石墨烯材料，再通过化学沉积制备了氧化石墨烯/硫复合物制备锂硫电池正极材料，并通过煅烧使硫分布更加均匀。摸索出制备过程的一些最佳的工艺条件同时，对粉末进行X射线衍射分析、透射电子显微镜（TEM）检测、并测试其导电性能。首次放电容量为 960 mAh/g，第3次开始以0.1C倍率充放电，循环降至 800 mAh/g，但是 50 次循环后容量保持600 mAh/g，库仑效率为 96.7%。以上结果表明氧化石墨烯-硫复合材料具有非常好的循环稳定性和库仑效率。

关键字：锂-硫电池 硫 氧化石墨烯 化学沉积

Lithium sulfur batteries positive sulfur/composite materials preparation and performance of graphene research

Abstract

Elemental sulfur , as a cathode material of the rechargeable Li-S battery , has a high theoretical gravimetric energy density of 1675mAh/g , moreover , it is inexpensive, abundant on earth, and environmentally benign. So it is considered to be the most promising cathode materials for the next generation batteries. However, Li-S is facing many problem that constrain its widespread application. The main obstacles are its poor conducivity, volume expanding. Moreover, sulfur can be reduced the polysulfide ions and dissolved into electrolyze in the discharge process and therefore causes the loss of active materials. In order to overcome these difficulties, this article through consulting a large number of documents and relevant materials, graphene and sulfur compound methods to improve the material performance. By improving its first prepared the graphene oxide, again through the CVD graphene oxide was prepared/sulfur sulfur compound preparation of lithium battery cathode material, and through the burning sulfur distribution more uniform. For some of the best process conditions of preparation at the same time, the powder X-ray diffraction (XRD) analysis, transmission electron microscope (TEM), and test their electrical conductivity. First discharge capacity is 960 mAh/g, third time start at 0.1 C ratio to charge and discharge, circulation fell to 800 mAh/g, but after 50 times cycle capacity maintain 600 mAh/g, coulomb efficiency is 96.7%. The above results show that graphene oxide sulfur composite material has the very good cycle stability and coulomb efficiency.

Key Words：Lithium sulfur batteries; sulfur; Oxidation of graphene;chemical deposition

目 录

摘 要 I

ABSTRACT II

第一章 引言 1

1.1锂硫电池的研究背景 1

1.2含单质硫复合正极材料的研究现状 1

1.2.1碳/硫复合材料 1

1.2.2导电聚合物/硫复合材料 3

1.2.3含氧化物的硫复合材料 4

1.3课题研究内容、研究途径和实验内容及方法 5

第二章 制备工艺及研究方法 6

2.1 主要原料及试剂 6

2.2 主要实验设备 6

2.3 材料表征方法 7

2.3.1差热-热重分析（TG-DSC） 7

2.3.2 X-射线衍射分析(XRD) 7

2.3.3扫描电子显微分析(SEM) 8

2.3.4透射电子显微镜（TEM） 8

2.3.5傅里叶变换红外光谱（FT-IR）测试 8

2.4 电学性能的测试 8

2.4.1工作电极的制备及扣式电池的组装 8

2.4.2充放电循环测试 9

第三章 氧化石墨烯材料的制备与性能研究 10

3.1 引言 10

3.2制备方案 10

3.3性能研究 10

3.3.1 X 射线衍射分析 10

3.3.2红外光谱分析 11

3.4小结 12

第四章 氧化石墨烯/硫复合材料的制备与性能研究 13

4.1实验方案 13

4.2实验结果与分析 13

4.2.1 X 射线衍射分析 13

4.2.2TEM分析 14

4.2.3 TG分析 14

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