1、 硕士学位论文论文题目:以木质素为碳源介孔碳及其复合材料制备和电化学中的应用作者姓名 指导教师 学科专业 材料学 所在学院 材料科学与工程学院 提交日期 浙江工业大学硕士学位论文I以木质素为碳源介孔碳及其复合材料制备和电化学中的应用摘 要多孔碳材料具有来源丰富、化学和热性能稳定、易于加工等优点,在超级电容器电极、固体氢存储等领域具有广泛的应用前景。介孔碳(MPCs)是多孔碳中被研究较多的品种,已被广泛用作催化剂载体及吸附剂。最近,又被拓展应用于电容器和储氢材料。木质素是植物中一种重要的支撑物质,其储存量仅次于纤维素,具有环境友好、可再生等优点。本文选用木质素为碳源,研究了介孔碳的制备、结构及其
2、在电化学中应用。研究表明,将金属氧化物负载于介孔碳表面,可显著提高介孔碳的电子传导率和倍率性能。主要内容及结果如下:(1)介孔碳材料。本文以木质素磺酸盐作为碳源,低分子量多聚甲醛/戊二醛为交联剂,聚乙烯吡咯烷酮(PVP)为分散剂,通过水热法合成的棕色固体为碳前体。 KOH/ ZnCl2 为扩孔剂对碳前体扩孔,最后在管式炉中煅烧制备得到了介孔碳材料。所得介孔碳材料具有较高比表面积,孔容大、孔径分布窄,并且介孔碳的碳壁已被大量石墨化,因此可作为电池的理想电极材料。组装电池后的恒流充放电测试表明介孔碳电极具有较高的比电容,且其 1000 次循环伏安测试结果也呈现了高的循环稳定性。这是由于介孔结构不会
3、限制离子传输,使其具有优良的大电流充放电性能。 (2)MPCs /NiO 复合材料。以 Ni(NO3)26H2O 为 Ni 源,将上述介孔碳材料作为载体,在碱性条件下回流冷凝,使 Ni+能够大量负载在浙江工业大学硕士学位论文II介孔碳材料表面,再于管式炉中煅烧,形成以多孔碳为骨架、NiO 纳米粒子良好分散的 MPCs /NiO 复合材料。由于 NiO 填充碳孔,使介孔碳的孔容及比表面积均有不同程度下降。将 MPCs /NiO 复合材料组装成电池,对其恒流充放电测试表明其具有较好的比电容,1000 次循环伏安测试显示具有优良的循环稳定性。其原因是由于 NiO 的赝电容及介孔碳材料的骨架结构,提高
4、了 MPCs /NiO 复合材料的电化学稳定性。关键词:介孔碳,木质素,介孔碳/氧化镍 ,电化学浙江工业大学硕士学位论文IIIPREPARATION AND ELECTROCHEMICAL PERFORMANCE OF LIGNIN-DERIVED MESOPOROUS CARBON AND ITS COMPOSITESABSTRACTPorous carbons have many advantageous properties with respect to their utility in electrochemical energy field, which requires cons
5、trained space such as electrode material of supercapacitor or solid-state hydrogen storage. The attractive properties of porous carbons include their abundance, chemical and thermal stability, feasible processability and so on. Mesoporous carbons (MPCs), which have been explored more than other carb
6、on classes, have been traditionally used as catalyst supports or adsorbents, but lately they are increasingly empolyed or finding potential applications in the fabrication of aforementioned materials.Lignin is a kind of important support materials in plants, who keep xylem hard to bearing the weight
7、 of the whole plant. Because of lignins high reserves next to cellulose in the world, it is a sort of environmentally benign and renewable natural resource. This article presents the preparation and characterization of liginin-devived MPCs, emphasizing on the use of low-cost and facilitate carbon pr
8、ecursor and tethering porous morphology. And in consideration of its hierarchical porosity, the lignin-derived MPC can be the matrix material of supercapacitor that improves an excellent electron conduction and rate performance. The main contents of this dissertation are summarized below:(1) Mesopor
9、ous carbons (MPCs). MPCs were 浙江工业大学硕士学位论文IVsynthesized by using the liginsulfonate, obtained from the pollution of paper industry, as carbon sources, glutaraldehyde/paraformaldehyde as cross-linking agents and polyvinylpyrrolidone (PVP) as a dispersing agent. The precursors for MPCs, appeared biste
10、r solids, were synthesized by hydrothermal and solvothermal methods. KOH or ZnCl2 were used as pore-enlarging agents. After that, the crude products were calcinated and charred in a horizontal tube furnace. The as-synthesized MPCs have high specific surface areas, large pore volumes and narrow pore
11、size distributions and almost porewalls of the MPCs have been graphitized, which endorse MPCs as leading candidates in application of electrochemical materials. Additionally, the fabricated capaciters showed a high specific capacitance in a constant current charge and discharge test and displayed a
12、good retention for more than 1000 cycles in a cycling test. Furthermore, because of the mesoporous structure that will not limit the ion motion within the pores, the activated carbon showed a good rate capability. (2) MPCs /NiO composites. The MPCs/NiO composites were synthesized via the sol-gel pro
13、cess using Ni(NO3)26H2O as a nickel source and the MPCs as matrix. In order to load the Ni+ on the MPCs, the mixture were refluxed in alkaline conditions. The MPCs/NiO composites were finally synthesized by drying in vacuum and calcining in a horizontal tube furnace. Specific surface area and pore v
14、olume of the MPCs/NiO composites all decreased due to NiOs filling of the carbon pore. The fabricated battery showed a dood specific capacitance in a constant current charge and discharge test and displayed a nice retention for more than 1000 cycles in a cycling test. NiOs pseudocapacitance 浙江工业大学硕士
15、学位论文Vand MPCss good structure make the MPCs/NiO composites good electrochemical properties.KEY WORDS: Mesoporous carbon; Lignin; Mesoporous carbon/nickel oxide; Electrochemistry浙江工业大学硕士学位论文VI浙江工业大学硕士学位论文VII目 录摘 要 .IABSTRACT.III第 1 章 文献综述 .11.1 引言 .11.2 介孔碳材料 .11.2.1 无序介孔碳 .21.2.2 以介孔硅为模板合成的统一介孔尺寸的碳
16、.31.2.2.1 多种孔结构的有序介孔碳的合成 .31.2.2.2 超大介孔碳 .51.2.2.3 孔壁石墨化的介孔碳 .71.2.2.4 合成方法高效、直接的介孔碳 .81.3 木质素 .101.3.1 木质素的简介 .101.3.2 木质素分子的结构 .111.3.3 木质素制备活性炭的研究 .111.4 介孔碳材料在电化学中的应用 .121.4.1 锂电池正极 .121.4.1.1 介孔碳材料用于锂电池正极 .121.4.1.2 结合金属或氧化金属的介孔碳用于电池正极 .131.4.2 超级电容器中的应用 .141.4.2.1 不含金属的介孔碳材料 .141.4.2.2 金属氧化物/介
17、孔碳材料 .151.5 研究意义和研究内容 .151.5.1 研究意义 .151.5.2 研究内容 .161.5.3 研究方法 .171.5.4 特色和创新之处 .17第二章 介孔碳的制备与电化学性能表征 .192.1 引言 .192.2 实验部分 .202.2.1 主要原料 .202.2.2 实验仪器及设备 .202.2.3 介孔碳的合成方法 .212.2.4 介孔碳的合成机理 .222.3 材料的表征 .222.3.1 扫描电镜(SEM) .222.3.2 高分辨率透射电镜(HRTEM) .232.3.3 氮气吸附测试(BET) .232.3.4 激光拉曼光谱仪(RAM) .232.3.5
18、 X 射线光电子能谱仪( XPS) .232.3.6 材料的电化学性能表征 .242.3.6.1 恒流充放电测试(Charge/ Discharge test) .24浙江工业大学硕士学位论文VIII2.3.6.2 循环伏安分析(CV) .242.4 结果与讨论 .242.4.1 高分辨透射电镜(HRTEM)和扫描电镜(SEM)测试 .242.4.2 氮气吸附测试(BET) .262.4.3 拉曼分析 .302.4.4 XPS 分析 .312.4.5 电化学性能表征 .332.4.5.1 循环伏安测试(CV) .332.4.5.2 循恒流充放电(Charge/ Discharge Test)
19、.342.5 本章小节 .36第三章 MPCs/NiO 复合材料的制备以及电化学性能表征 .373.1 引言 .373.2 实验部分 .383.2.1 主要原料 .383.2.2 实验仪器及设备 .383.2.3 MPCs/NiO 复合材料的制备方法 .393.2.4 MPCs /NiO 复合材料的合成机理 .403.3 材料的测试及表征 .403.3.1 X 射线衍射分析(XRD) .403.3.2 扫面电镜(SEM) .413.3.3 高分辨率透射电镜(HRTEM) .413.3.4 氮气吸附测试(BET) .413.3.5 热重测试(TG) .413.3.6 材料的电化学性能表征 .413.3.6.1 恒流充放电(Charge/ Discharge Test) .413.3.6.2 循环伏安测试(CV) .423.4 结果与讨论 .423.4.1 X 射线衍射分析(XRD) .423.4.2 高分辨透射电镜(HRTEM)和扫描电镜(SEM)测试 .433.4.3 氮气吸附测试(BET) .453.4.4 热重测试(TG) .473.4.5 材料的电化学性能表征 .483.4.5.1 循环伏安测试(CV) .482.4.5.2 恒流充放电(Charge/ Discharge Test) .503.5 本章小节 .54第四章 结论、创新点和展望 .