【作者】 杨思远；

【导师】 贾铮；

【作者基本信息】 哈尔滨工业大学 ， 化学工程与技术， 2011， 硕士

【摘要】 锂离子电池与超级电容器是最具希望的两种电化学储能设备,而提高其性能的最为有效的方法无疑是研究与制备性能优良的新型材料。硅是一种重要的锂离子电池负极材料,本文使用一种新颖的液相合成的方法,制备出丁基包覆的硅纳米材料,再对其进行高温烧结,得到碳包覆的硅纳米材料,详细的研究了制备的各种硅材料的电化学性能。高比表面积的活性炭是良好的超级电容器电极材料,本文采用氢氧化钠活化石油焦的方法制备了高比表面积的活性炭材料,探索了超级电容器的装配工艺,并研究了不同制备条件对材料性能的影响。首先,优化了丁基包覆硅纳米材料的合成工艺,制备出的材料大小适当、分布均匀,经测试发现其尺寸在50nm左右。对材料进行烧结,使用传统的管式炉烧结的方法得到的材料循环性能良好,经改进烧结工艺后最高脱锂比容量可达410.31mAh/g。使用真空烧结的实验装置能够有效阻止材料有效物质的气化流失,制得的材料中碳与硅结合紧密、包覆均匀,各种电阻相比明显下降,显著的提高了材料的电化学性能,其最高脱锂比容量可达663.25mAh/g且70次循环后容量没有明显的衰减。其次,研究了不同粘结剂体系对硅材料性能的影响,揭示了粘结剂影响电池性能的本质。发现使用CMC水性粘结剂体系代替传统的PVDF体系粘结剂能够有效的提高纯硅材料的循环性能,而对于碳包覆硅纳米材料,使用PVDF粘结剂时效果较好。最后,系统的研究了活性炭材料超级电容器的电化学性能,揭示了材料的结构对其性能的影响。石油焦为碳源,700℃下使用氢氧化钠活化1h时,得到活性炭材料在1mV/s下的比电容能够达到68.78F/g,100mV/s下比电容保持效率为47.52%。而预氧化处理能够显著的提高材料的性能。经预氧化处理的活性炭材料1mV/s下的比电容能够达到83.47F/g,在100mV/s的高扫速下仍有68.75F/g,比电容保持效率为77.57%。更多还原

【Abstract】 Lithium-ion batteries and super capacitors are two most promising electrochemical energy storage devices. And the most effective way to improve its performance is to develop new materials. Silicon is an important lithium-ion battery anode material. In this paper, one kind of butyl-coated silicon nano-materials was prepared by the certain original liquid phase synthesis, then the carbon-coating silicon nanomaterials was prepared after high-temperature sintering, and took related tests of physical characterizations and electrochemical performances. Active carbon is a kind of good super capacitor electrode. This article used petroleum coke as the carbon source; and prepared a carbon material witn high surface area by activation of sodium hydroxide. Explore the assembly process of super capacitors, and study the relationship between different preparation conditions and material properties.Firstly, in this paper, it optimized the experimental conditions gradually, to prepare one kind of butyl-coated silicon nano-materials with proper size, and uniform distribution. After tests founded that its size was about 50nm with excellent distribution. Took a further process of high-temperature sintering in a tube furnace, the materials got shaw a good cycling properties, the maximum specific capacity of lithium-extracted was 410.31mAh/g. The gasification loss of active materials could be improved effectively through the method of vacuum sintering, by which obtained the silicon-coated carbon nano materials of better electrochemical properties and carbon-coating equably. Its maximum specific capacity of lithium-extracted reached to 663.25mAh/g, with excellent cycling properties and no obvious capacity attenuation after 70 cycles.Secondly, The study of the influences of silicon material in different binder systems was carried. Which revealed the nature of how the binder affect battery performance. Discovered that cycle properties of pure silicon could be improved when using CMC of water-based adhesive system instead of the traditional PVDF. However, when applied in carbon-coating silicon nano-materials PVDF is better.Finally, studied the electrochemical properties of the super capacitors when using activatied carbon as electrode materials. Revealed the relationship between the structure of the materials and its performance. Using petroleum coke as the carbon source, activation at 700℃with NaOH, the specific capacitance of the activatied carbon got under 1mV/s was 68.78F/g. The retention efficiency under 100mV/s was 47.52%. However, the activation process before joining hydrogen peroxide to pre-oxidation can improve the carbon material’s performance significantly. The specific capacitance under 1mV/s reached to 83.47F/g. It still remained 68.75F/g under 100mV/s. The retention efficiency was 77.57%.更多还原