CAS OpenIR  > 研究所(批量导入)
过渡金属氧化物多壳层空心球的合成及其储能性质的研究
王江艳
学位类型博士
导师王丹
2015-09
学位授予单位中国科学院研究生院
学位授予地点北京
学位专业材料学
关键词过渡金属氧化物 多壳层空心结构 锂离子电池 超级电容器
其他摘要

能源短缺和环境污染,是当今也是未来全球发展的核心问题。开发高效节能、绿色环保的新能源成为有效缓解甚至解决这些问题的关键。锂离子电池与超级电容器因其各自鲜明的特点和优势,从众多能源转换与存储装置中脱颖而出,引起了人们的广泛关注。然而,它们的进一步发展都受限于一系列的问题,比如能量密度偏低,稳定性有待提高等等。本研究针对目前存在的这些问题,从材料的设计和可控合成出发,制备了一系列的多壳层金属氧化物空心微纳米结构,并将其用作锂离子电池和超级电容器的电极材料,以期改善现有状况并进一步提高二者的综合性能,取得了一些阶段性的研究成果,主要内容如下:1. 针对四氧化三钴(Co3O4)在锂离子嵌入-脱出过程中体积膨胀大,结构易破坏,电池循环寿命短等问题,通过采用碳微球模板法以及一系列辅助策略来强化碳模板对金属前驱体盐的吸附,设计合成出尺寸与形貌十分均匀的多壳层Co3O4空心球。将这些多壳层Co3O4空心球用作锂离子电池负极材料,展示出了十分优异的循环性能和极高的比电容量(电流密度为50 mA/g,循环三十次后,三壳层空心球的放电比容量为1615.8 mAh/g),并且电池的倍率性能也得到了很大提高。2. 采用五氧化二钒(V2O5)取代目前商业使用的正极材料,可进一步提高锂离子电池的总体比电容量。然而其在充放电过程中发生的剧烈相变及由此导致的结构不稳定,限制了它在锂离子电池中的应用。针对这一问题,本研究基于一种新的合成理念,即阴离子相互竞争地吸附在碳球模板上,并通过Trojan催化燃烧去除模板,制备得到了V2O5多壳层/多腔体空心结构。通过调控合成条件,产物的壳层数、壳壁厚度、孔径分布以及结晶性等参数都得到了很好的控制。受益于多壳层空心球的结构优势,V2O5多壳层空心结构展现出了创纪录的比容量、优异的循环稳定性(电流密度为1000 mA/g时,首次循环和100次循环后的比容量分别为447、402 mAh/g)和倍率性能,为高能量及高功率密度锂离子电池的设计与开发提供了新的思路。3. 锂离子电池的能量密度取决于比容量和电压窗口两个因素。三氧化二铬(Cr2O3)作为锂离子电池负极材料,不仅理论比容量比Co3O4,Fe2O3的更高而且放电电压平台更低,极具发展前景。然而其在充放电过程中也存在着结构易破坏,电化学连接性变弱,循环稳定性下降等一系列问题。针对这些问题,本研究通过调控碳球模板的尺寸及金属盐吸附时间,控制铬前驱体在碳球中的吸附量和嵌入深度,成功制备出了单、双、三、四和五壳层Cr2O3空心球。将其用作锂离子电池负极材料,表现出了优于以往所有报道的基于Cr2O3微纳米结构的锂离子电池性能。4. 多壳层空心结构不仅能够应用于锂离子电池,而且在超级电容器中也有十分显著的应用优势。本研究设计合成了三氧化二锰(Mn2O3)多壳层空心球,并精确控制了空心球的壳层数、壳壁厚度、晶粒尺寸等结构参数,解决了Mn2O3材料实际比表面积低,离子以及电子传导性差,易溶解在电解液中等问题。用作超级电容器电极材料,极大地提高了超级电容器的比电容量(电流密度为0.5 A/g时,三壳层空心球的比电容量为1651 F/g),并改善了其循环性能以及倍率性能。

;

Energy shortage and environmental pollution have become essential problems for the global world nowadays, which can be remitted or even settled down by developing effective and environment-friendly energy and sources. Among various kinds of energy storage and exchange systems, lithium-ion batteries (LIBs) and supercapacitors (SCs) have drawn great attention due to their obvious advantages. However, the further development and wider application of LIBs and SCs have been suffered from a series of problems, such as low accessible energy density, poor cycling stability and so forth. In this thesis, by starting from the design and controlled synthesis of hollow micro-/nanostructures, we develop a series of multi-shelled metal oxide hollow micro/nanostructures as electrode materials for LIBs and SCs, trying to solve the current remained problems and further improve their performance. Some results are obtained and listed below:1. Although Co3O4 as anode materials for LIBs, can greatly improve the specific capacity, the large volume-expansion can result in severe damage to the structure, leading to a poor cycling performance, thus largely hindered its practical use in LIBs. To solve these problems, we prepare multi-shelled Co3O4 hollow microspheres with uniform size and high yield and purity by enhancing the precursor-adsorption of carbonaceous microsphere (CMS) templates through a series of methods. When used as the anode material for LIBs, they show high specific capacity, long cycle life, and superior rate capability (1615.8 mAh/g remained at the 30th cycle for the triple-shelled at a current density of 50 mA/g).2. Using V2O5 to replace the current commercial cathode materials can further improve the total capacity of the full LIBs. However, their poor structural stability induced by irreversible phase transitions upon deep discharge limited their applications in LIBs. Here, we put forward and verify a new concept of anions-adsorption by negatively-charged CMS templates through deeply exploiting the mechanism. And followed with a Trojan catalytic combustion process to remove the templates, hollow V2O5 microspheres with multiple shells or cavities are developed. Besides, the shell number, shell thickness, porosity and crystallinity are accurately controlled. Benefited from the large surface area, short electron/ ion transport length, high structural stability, LIBs based on multi-shelled V2O5 hollow microspheres cathode material show new-record high capacity, stable cycling performance and good rate capability (at a current density of 1000 mA/g, 447 and 402 mAh/g was achieved for the first and the 100th cycle, respectively). This study opens a new insight into the development of next-generation LIBs with high energy density and power density.3. The energy density of LIBs depends on both the specific capacity and the voltage range. Cr2O3 has been considered as a promising anode material of LIBs for a long time, owning to its higher theoretical capacity and lower plateaus than other transition-metal oxides such as Co3O4 and Fe2O3. However, the actual application of Cr2O3 still suffers from poor cycling performance caused by the huge volume variation, pulverization, electrical contact loss during the lithium insertion/extraction processes. To solve these problems, we synthesize single-, double-, triple-, quadruple-, quintuple-shelled Cr2O3 hollow microspheres by adjusting the size of the templates as well as the adsorption duration. As anode materials for LIBs, these multi-shelled Cr2O3 hollow microspheres show the best LIB performance to date.4. Multi-shelled hollow structures can not only be used in LIBs, but also show great application advantages in Supercapacitors (SCs). Here, we prepared multi-shelled Mn2O3 hollow microspheres, and accurately controlled their structural parameters such as shell number, shell thickness and grain size. Profited from the structural superiorities of multi-shelled hollow structures, the problems of Mn2O3 such as low specific surface area, poor electron/ion transport ability, and partial dissolution in electrolyte are well solved. When used as the electrode materials for SCs, the specific capacity, cycling performance and the rate capability of SCs are all greatly improved (1651 F/g at a current density of 0.5 A/g for the triple-shelled). 

语种中文
文献类型学位论文
条目标识符http://ir.ipe.ac.cn/handle/122111/21356
专题研究所(批量导入)
推荐引用方式
GB/T 7714
王江艳. 过渡金属氧化物多壳层空心球的合成及其储能性质的研究[D]. 北京. 中国科学院研究生院,2015.
条目包含的文件
文件名称/大小 文献类型 版本类型 开放类型 使用许可
王江艳-毕业论文 博士.pdf(10659KB)学位论文 开放获取CC BY-NC-SA浏览 请求全文
个性服务
推荐该条目
保存到收藏夹
查看访问统计
导出为Endnote文件
谷歌学术
谷歌学术中相似的文章
[王江艳]的文章
百度学术
百度学术中相似的文章
[王江艳]的文章
必应学术
必应学术中相似的文章
[王江艳]的文章
相关权益政策
暂无数据
收藏/分享
文件名: 王江艳-毕业论文 博士.pdf
格式: Adobe PDF
所有评论 (0)
暂无评论
 

除非特别说明,本系统中所有内容都受版权保护,并保留所有权利。