率和长循环的储锂性能 ( 在 1A g -1 下循环 200 周比容量达 600 mah g -1 ) 和储钠性能 ( 在 0.1 A g -1 下循环 200 周比容量达 mah g -1 ; 在 1 A g -1 下循环 500 周比容量达 mah g -1 ) 2

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1 博士学位论文公示材料学生姓名王丹学号二级学科材料学导师姓名齐西伟论文题目三维多孔碳及锡基合金纳米结构的原位构筑与储锂 ( 钠 ) 性能研究论文研究方向锂钠离子电池负极材料论文关键词锂离子电池, 钠离子电池, 负极材料, 多孔碳, 掺杂, 锡基合金论文摘要 ( 中文 ) 电动汽车智能电网等大规模储能技术的大力发展对锂离子电池的能量密度和功率密度都提出了更高的要求与此同时, 锂矿价格上涨和储量匮乏的问题也日益凸显因此, 在全面提升锂离子电池性能的同时, 开发新的储能技术也势在必行近年来被大家广泛关注的钠离子电池不但具有与锂离子电池相似的储能原理, 而且原料丰富价格低廉, 是最有发展前景的储能技术之一为了获得高性能的锂钠离子二次电池, 开发高容量大倍率长循环低成本的电极材料至关重要碳材料 ( 如石墨 ) 具有来源丰富导电性好稳定性好等优势, 已经被广泛应用于锂离子电池负极材料 ; 但其有限的比容量和较差的倍率性能限制了其进一步发展, 尤其是在钠离子电池领域的应用锡属于合金型负极材料, 具有多电子反应机制, 理论比容量非常高 ; 但由于锡在合金化过程中体积膨胀严重, 因此循环稳定性较差, 尚不能实现商业化应用针对上述问题, 本文以碳基材料和锡基材料为研究目标, 通过溶盐模板辅助 - 原位热解法可控合成了氮掺杂的三维多孔碳硼掺杂的三维多孔碳多孔碳 / 镍锡合金多孔碳 / 锡锑合金复合材料 ; 并探究了所合成材料的储锂储钠性能及反应机制具体研究内容如下 : (1) 分别以柠檬酸和葡萄糖为碳源尿素为氮源氯化钠为模板, 采用单模板辅助 - 原位热解法制备了氮掺杂的三维多孔碳材料结果表明, 所合成的材料具有互相贯穿的非晶多孔碳网络, 比表面积高达 265~425 m 2 g -1 多种形式的( 吡啶 N 吡咯 N 和石墨 N) 高含量的( 掺入的原子比最高可达 12%) 氮掺杂使碳的无序度增加将其用于钠离子电池负极表现出了优异的循环性能 ( 在 0.1 A g -1 下循环 100 周容量保持 416 mah g -1 ) 和突出的倍率性能 ( 在 5 A g -1 下比容量为 mah g -1 ;10 A g -1 下循环 1000 周容量为 142 mah g -1 ), 远优于未掺氮的碳材料 (2) 以柠檬酸为碳源氯化钠为第一模板硼酸为硼源和第二模板, 采用双模板辅助 - 原位热解法制备了硼掺杂的三维分级多孔碳材料结果表明, 双模板原位热解同时实现了分级多孔碳的原位构筑和硼元素的均匀掺入得益于其独特的结构优势, 硼掺杂的三维多孔碳材料显示出了优异的储锂性能 ( 在 0.1 A g -1 下 100 周循环后容量保持 460 mah g -1, 在 5 A g -1 下比容量达 220 mah g -1 ) 和储钠性能 (0.1 A g -1 下 100 周循环后容量保持 200 mah g -1 ; 在 5 A g -1 下比容量达 127 mah g -1 ) (3) 为了将多孔碳材料高导电性高稳定性的优势与锡基材料高容量的优势相结合, 我们采用模板辅助 - 原位热解法制备了镍锡合金与三维多孔碳复合的负极材料结果显示, 纳米尺度 (10~30 nm) 的镍锡合金 (Ni 3Sn 2 和 Ni 3Sn 4) 能够牢固而均匀地镶嵌在三维多孔碳网上 ; 同时合金颗粒表面覆盖有石墨化的碳包覆层这种结构一方面通过合金化纳米化和碳包覆缓解了锡在充放电过程中的体积变化, 使其循环性能大大提高 (Ni 3Sn 4/C 在 0.5 A g -1 下循环 200 周比容量达 732 mah g -1 ); 另一方面, 三维多孔的结构在进一步有效缓解体积膨胀的同时, 还提高了电极材料的导电性, 改善了动力学反应速率, 使其倍率性能也得到改善 (Ni 3Sn 4/C 在 5 A g -1 下比容量达 377 mah g -1 ) (4) 为了进一步提高电极材料的容量, 避免引入惰性基体导致电极容量的牺牲, 本章选用了具有电化学活性的金属锑作为抑制元素, 制备了锡锑合金与三维多孔碳复合的负极材料 SnSb@SnO x/sbo x@c 结果显示, 锡锑合金能够牢固而均匀地镶嵌在三维多孔碳网上, 呈蛋黄壳状的结构 SnSb@SnO x/sbo x@c 的内核为纳米锡锑合金, 次外层为锡和锑的非晶氧化物, 最外层是石墨化的碳包覆层这种蛋黄壳状的结构很大程度上缓解了锡锑纳米颗粒的团聚长大和体积变化该结构设计既保证了锡锑合金高比容量的发挥, 同时又为锡锑合金化过程中的体积变化提供了缓冲空间, 还增加了电解液的浸润性, 缩短了离子扩散路径, 改善了材料的导电性, 进而使其实现了高容量大倍 1

2 率和长循环的储锂性能 ( 在 1A g -1 下循环 200 周比容量达 600 mah g -1 ) 和储钠性能 ( 在 0.1 A g -1 下循环 200 周比容量达 mah g -1 ; 在 1 A g -1 下循环 500 周比容量达 mah g -1 ) 2

3 论文摘要 ( 英文 ) With the great development of electronic vehicle (EC), smart power grids and large-scale energy storage technology, the demands on energy density and power density of lithium ion batteries (LIBs) are increasing. At the same time, the problems of rare reserve and high price of lithium are also focused. Therefore, on the one hand, it s necessary to improve the electrochemical performance of lithium ion battery; on the other hand, it s also quite important to implore new energy storage technology. Sodium ion batteries (NIBs) own the similar physical and chemical property with LIBs, and they show abundant reserves and low price, which made them the most important candidate for the secondary battery. In order to prepare LIBs and NIBs with perfect electrochemical performance, the most important thing is to explore excellent electrode materials with high capacity, good rate performance, long lifetime and low price. As the most widely used anode material, carbon owns many advantages such as abundant reserves, high conductivity and high stability. But the theoretical capacity of carbon is not quite high. In contrast, alloy electrode material especial Sn expresses super high capacity. However, because of its terrible volume expansion, a poor structure stability and fast capacity attenuation always appear, which hampered its practical application. Focus on the problems mentioned above, three dimension (3D) porous carbon with N/B doping, Ni-Sn/C and SnSb/C composites have been synthesized by template-assisted in situ pyrolysis method. The electrochemical performance and storage mechanism of LIBs and NIBs with the obtained anode were discussed. The specific research contents are list as follows: (1) N-doped 3D porous carbon is synthesized by template-assisted in situ pyrolysis method, using citric acid/glucose as carbon resource, urea as nitrogen resource, and sodium chloride (NaCl) as template. The results show that N has uniformly doped into 3D porous carbon with a high content of 12%. N-doped 3D porous carbon with high specific surface area of 265~425 m 2 g -1 exhibits higher capacity, excellent cycle performance and perfect rate capacity compared with 3D porous carbon without N doped (at 0.1 A g -1 after 100 cycles: 416 mah g -1 ; at 5 A g -1 : mah g -1 ). (2) B-doped 3D porous carbon is synthesized by template-assisted in situ pyrolysis method, using citric acid as carbon resource, boric acid as boric resource and template, and sodium chloride (NaCl) as another template. B-dope 3D porous carbon exhibits high capacity, excellent cycle performance and perfect rate performance in both LIBs (at 0.1 A g -1 after 100 cycles 460 mah g -1 ; at 5 A g -1 : 220 mah g -1 ) and NIBs (at 0.1 A g -1 after 100 cycles: 200 mah g -1 ;at 5A g -1 : 127 mah g -1 ). (3) In order to take full advantage of the high capacity of Sn and high conductivity and stability of 3D porous carbon, Ni-Sn/C composite is synthesized by template-assisted in situ pyrolysis method, using NaCl as template. The results show that nano Ni-Sn (Ni 3Sn 2 and Ni 3Sn 4) particles (10~30 nm) are uniformly dispersed on 3D porous carbon. The strong bonding force between Ni-Sn and C is ascribed to the in situ pyrolysis method. The 3D porous structures provide enough space for the volume expansion of Sn. Meanwhile, the carbon shell outside Ni-Sn nano alloy restricted the growth and agglomeration of NiSn nano particles. The Ni-Sn/C composites exits excellent cycle performance and rate performance in LIBs (at 0.5 A g -1 after 200 cycles: 732 mah g -1 ; at 5 A g -1 : 377 mah g -1 ). Because of the existence of non-electrochemical activity of Ni, Ni 3Sn 4/C exhibits more perfect electrochemical performance than Ni 3Sn 2/C. (4) In order to further improve the electrochemical performance of Sn-based materials, SnSb@SnO x/sbo x@c is synthesized. The results show that SbSn are uniformly dispersed on the carbon, and yolk-shell structures are formed. The XPS results show that SnSb nano particles were coated with tin oxide/antimony oxide and carbon. The unique yolk-shell structure can restrain the aggregation and grow of SnSb particle, and then reduce the volume expansion, improve the cycle and rate performance. This design not 3

4 only take full advantage of the high capacity of Sn base materials, but also provide enough space to tolerate the volume expansion, increase the wettability of electrolyte, shorten the diffusion path of ion, and improve the conductivity of the materials. As a result, the as-prepared sample exhibits excellent electrochemical performance in LIBs (1A g -1 after 200 cycles: 600 mah g -1 ) and in NIBs (0.1 A g -1 after 200 cycles: mah g -1, 1 A g -1 after 500 cycles: mah g -1 ). 4

5 论文主要创新点 1. 利用水溶性模板辅助的原位热解法可控制备了氮掺杂的三维超薄多孔碳材料, 氮掺杂量高达 12%, 氮的掺入大大增加了碳材料的缺陷和活性位点, 在扩散机制和电容机制共同作用下, 其获得了优异的电化学储钠性能 2. 利用水溶性双模板法可控制备了硼掺杂三维分级多孔碳材料, 由于硼酸兼具硼源和二级模板作用, 所制得的分级多孔碳显示出大的比表面积和丰富的孔隙结构, 在储锂和储钠方面显示出稳定的循环性能和突出的倍率性能 3. 通过溶盐模板辅助原位催化法构筑了三维多孔碳内嵌碳包覆纳米镍锡合金的复合结构, 该结构综合了纳米化合金化碳包覆及三维多孔碳复合等优势, 实现了该材料在锂离子电池负极中高容量长循环和高倍率性能的统一 4. 利用模板辅助原位催化热解法制备了锡锑合金 / 三维多孔碳复合材料, 证实了三层蛋黄壳状结构 ( 锡锑合金 / 非晶氧化物 / 石墨化碳壳 ), 在三层核壳结构与三维多孔碳的协同作用下, 材料显示出了极佳的电化学储锂储钠性能 5. 经实验测试及理论分析证明, 具有三维多孔的碳材料的电荷存储机制包含两部分, 一部分是由扩散控制的嵌入机制, 一部分是由于表面吸附产生的电容机制而且随着充放电电流密度的增加, 电容的贡献也显著增大攻读博士学位期间取得的学术成果注 : 按有关规范填写本人为第一作者或导师是第一作者本人为第二作者, 且第一署名单位为东北大学的研究成果 [1] Dan Wang, Zhiyuan Wang, Yuan Li, Shaohua Luo, Kangze Dong, Yanguo Liu, Xiwei Qi. Template-assisted in-situ confinement synthesis of nitrogen and oxygen co-doped 3D porous carbon network for high-performance sodium-ion batteries anode [J]. New Journal of Chemistry,2018, 42, (SCI, 第 3 章 ) [2] Dan Wang, Zhiyuan Wang, Yuan Li, Kangze Dong, Jiahui Shao, Shaohua Luo, Yanguo Liu, Xiwei Qi. In situ Double-Template Fabrication of Boron-Doped 3D Hierarchical Porous Carbon Network as Anode Materials for Li- and Na-ion Batteries [J]. Applied Surface Science,2018, 42, (SCI, 第 4 章 ) 5

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24-2_cover_OK 2 08 Flexible All Solid State Thin Film Li-ion Battery 1 1 2 1 1 2 ( 300Wh/kg) (3.4~3.8 V) ( 1000 cycles) (LiCoO 2 ) (LiPON) (Mica) 26mAhcm -2 mm -1 30 85% LED Abstract With the ever-changing technology,

率和长循环的储锂性能 ( 在 1A g -1 下循环 200 周比容量达 600 mah g -1 ) 和储钠性能 ( 在 0.1 A g -1 下循 环 200 周比容量达 mah g -1 ; 在 1 A g -1 下循环 500 周比容量达 mah g -1 ) 2

率和长循环的储锂性能 ( 在 1A g -1 下循环 200 周比容量达 600 mah g -1 ) 和储钠性能 ( 在 0.1 A g -1 下循环 200 周比容量达 mah g -1 ; 在 1 A g -1 下循环 500 周比容量达 mah g -1 ) 2