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题名 高性能锂离子电池硅/锗电极的设计与制备
姓名 杨智博
院系 物理科学与技术学院
专业 凝聚态物理
学位名称 理学博士
外文题名 Design and Fabrication of High Performance Si/Ge Anode for Lithium-Ion Batteries
第一导师姓名 贺德衍
关键词 锂离子电池;阳极材料;纳米结构;硅;锗;薄膜沉积
外文关键词 Lithium-ion battery;anode material;nanostructure;silicon;germanium;thin film deposition
学科 理学
摘要 开发具有高能量密度、高功率密度和长循环寿命的锂离子电池对于电动/混合动力汽车的普及、便携式电子设备的更新换代以及可再生能源的利用等具有重要的意义。目前商用的锂离子电池的负极材料主要为石墨,其理论比容量仅为372 mA h/g,制约了锂离子电池性能的进一步提高,因此,发展具有更高比容量的负极材料至关重要。 在室温下,Si和Ge的理论储锂比容量分别高达3579和1384 mA h/g,是最具发展潜力的大容量锂离子电池负极材料。然而,这类材料在锂离子嵌入和脱出的过程中通常伴随着超过300 %的体积形变,容易引起电极材料粉碎,导致容量的快速衰减。同时,Si和Ge作为典型的半导体材料,其电导率较低,作为电极材料时倍率性能往往有待提高。 本论文以抑制Si和Ge 材料电极粉末化、提高Si和Ge 电极的循环稳定性和大倍率充放电性能为目标,以制备类薄膜Si和Ge纳米材料为突破口,开展了材料的纳米结构优化设计、材料制备方法探索、材料结构、形貌和性能表征等几方面的研究。
外文摘要 At present, Li-ion batteries have been the vital power sources for mobile electronic devices. However, the currently used commercialized graphite anode only have a theoretical specific capacity of 372 mA h/g, which is hindering the development of Li-ion batteries. At room temperature, Si and Ge have theoretical specific capacities of 3579 and 1384 mA h/g, respectively, are considered as the most promising candidates for anodes of Li-ion batteries. But unfortunately, Si and Ge anodes always undergo a rapid capacity fading caused by severe volume change (~300%) during Li-ion insertion and extraction. Meanwhile, Si and Ge as the typical semiconductor materials, the conductivities are not high enough, which always leads to a poor rate performance. In this thesis, for the purpose of developing Li-ion batteries with improved rate capability and cyclability, we intend to design and fabricate Si and Ge thin film anodes on nanostructured current-collectors. And the obtained anodes was studied from the aspects of nanostructure optimization, fabricating-method exploration, micro-structure, morphology and electrochemical performance.
研究领域 新能源材料与器件
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