【作者】 魏书杰；

【导师】 瞿斌； 周新红；

【作者基本信息】 青岛科技大学 ， 应用化学， 2009， 硕士

【摘要】 锂离子二次电池以其优越的综合性能受到各国研究工作者和企业的广泛重视,大量的研究工作集中在寻找更高容量的新型负极材料上,负极材料的纳米化和结构功能化,认为是解决这些问题的有效方法。本文分别用水热法与溶胶凝胶法合成了以SnO2及TiO2为主体的锡基氧化物与钛基氧化物系列复合材料,并用透射电镜(TEM)、扫描电子显微镜(SEM)、X射线电子衍射(XRD)、热重(TG-DTA)等测试手段对材料进行了表征。最终将其以锂为对电极应用于锂离子电池作为电极材料,研究了它们的电化学性能特点。主要工作如下:以SnCl2为原料用水热法制备了SnO2纳米颗粒及掺杂了CuOx、NiOx的SnO2纳米复合物,对它们的结构及电化学性质进行了表征。由SEM图像可知,所制备的SnO2纳米复合物基本上为球形的,粒径大约在100 nm~300 nm。以K2SnO3为原料用水热法制备了SnO2纳米颗粒,再以所制备的SnO2纳米颗粒为原料制备了SnO2/碳水化合物及Sn/C纳米颗粒。由SEM、TEM图像可知,所制备的SnO2纳米颗粒粒径大约为150 nm,SnO2/碳水化合物其粒径大约为200 nm,而Sn/C纳米颗粒为核壳结构其壳的直径大约在100 nm~250 nm,而核的粒径为30 nm~200 nm。由XRD数据表明所得到Sn/C纳米颗粒是金属锡和碳的复合物,此外还有很少量的氧化亚锡存在。由充放电循环性能曲线可知碳含量的增加可以明显改善循环性能,而且在大电流充放电试验也表现出很好的倍率性能。因此,Sn/C纳米颗粒用作锂离子电池负极材料有较好的循环性能及倍率性能。通过溶胶-凝胶法制备了TiO2纳米颗粒及掺杂了Cu、Ni、Ru、Sn、Fe的TiO2纳米复合物。由SEM,TEM图像可知,所制备的TiO2纳米颗粒及TiO2纳米复合物均为无定形的,粒径大约在30 nm~50 nm。由XRD图像可知,所制备的TiO2纳米颗粒为锐钛矿相,无金红石相。由充放电循环性能曲线可知,所得到的TiO2纳米颗粒的循环性能较为稳定,在倍率为C/5的条件下经60次循环其可逆容量可维持在195 mAh/g。通过掺杂Ru,TiO2纳米颗粒的循环性能得到明显的提高。更多还原

【Abstract】 Lithium ion batteries have been paid much attention by world wide researchers and companies due to the advanced electrochemical properties, and have been developed quickly in recent years. A lot of researches have focused on finding new large capacity anode material candidates. The anode material with nanosized and peculiar structure was considered as an appropriate candidate.In this thesis, the anode materials based on SnO2 and TiO2 were prepared using the hydrothermal and Sol-Gel technique respectively. They were characterized by Transmission Electron Microscope(TEM), Scanning Electron Microscope(SEM), X-ray Diffraction(XRD), TG-DTA, and other techniques. They were used as the anode materials of the lithium ion battery, and their electrochemical performance were studied in detail. Our work is showed as the following:SnO2 nanoparticles and SnO2 nanocomposites were prepared by hydrothermal technique with SnCl2 as material. The structure and electrochemical property were characterized. The SEM images showed that the SnO2 nanocomposites were mainly spherical particles, and the radius was between 100 nm and 300 nm.SnO2 nanoparticles were prepared by hydrothermal technique with K2SnO3 as material, then the SnO2 nanoparticles were used to prepare SnO2/carbonhydrate and Sn/C nanocomposites. The SEM and TEM images showed that the radius of SnO2 nanocomposites, SnO2/carbonhydrate were 150 nm, 200 nm respectively. The radius of Sn/C nanocomposites was between 100 nm and 250 nm, and the core radius of Sn/C nanocomposites was between 30 nm and 200 nm. From XRD images, we found that Sn/C nanocomposites were composed of tin and carbon coexisting with a little amount of SnO. The cycle performance was improved obviously with increasing amount of carbon content, and the rate capability was excellent. So these materials which were used as lithium ion anode materials showed better cycle performance and rate capability.TiO2 nanoparticles and TiO2 nanocomposites with Cu, Ni, Ru, Sn, Fe were prepared by Sol-Gel technique. The SEM and TEM images showed that TiO2 nanoparticles and TiO2 nanocomposites were amorphous, and the radius was between 30 nm and 50 nm. From XRD images, we found that the phase of TiO2 nanocomposites was anatase without rutile. The stability of cycle performance was excellent, and the reversible capacity maintains 195 mAh/g with rate C/5 after 60 cycle. The cycle performance of TiO2 nanoparticles with Ru enhanced apparently.更多还原