内蒙古科技大学 本科生毕业论文
题 目：不同沉淀剂水热合成 Ni(OH)2及其表征 学生姓名：张庆海
学 号：201066115322 专 业：化学工程与工艺 班 级：化工10-3班 指导教师：赫文秀 教授
内蒙古科技大学本科生毕业论文
摘 要
镍氢电池作为一种高比能量的二次电池得到了广泛的应用。氢氧化镍作为镍氢电池的主要正极材料，其制备的研究对提高镍氢电池整体性能具有重要意义。
本实验以硝酸镍为镍源，以尿素为沉淀剂，用氢氧化钠调节pH，以水热法合成Ni(OH)2花瓣状微球，反应温度170℃，反应时间18h，干燥温度80℃，干燥时间24h。过程简单、易于操作。通过改变镍和尿素的配比，观察在不同配比的情况下，Ni(OH)2花瓣状微球的晶型结构、颗粒形貌的变化。并以硝酸镍为镍源，以氨水为沉淀剂，进行对比观察在以不同沉淀剂所合成的Ni(OH)2晶型结构、颗粒形貌的不同。
利用X射线衍射（XRD）和扫描电子显微镜(SEM)分别对合成试样进行物相和形貌分析，结果表明，随着镍尿素摩尔比的增加，Ni(OH)2粒径先减小然后增加，花瓣结构变得逐渐清晰，花瓣厚度逐渐减小，花瓣变得松散。其中最佳镍和尿素的配比为1:5。增加镍尿素摩尔比有利于β-Ni(OH)2的形成。增大硝酸镍溶液的浓度有利于球形氢氧化镍的形成。以尿素做沉淀剂优于氨水。
关键词：纳米材料；氢氧化镍；水热法；尿素；氨水
I
内蒙古科技大学本科生毕业论文
Abstract
Nickel hydrogen battery as a high energy density secondary batteries have been widely used.Nickel hydroxide as the main NiMH battery cathode materials, preparation of research to improve the overall performance of batteries is important.
Nickel nitrate as nickel source,urea as the source of nickel,and in order to regulate the pH of the solution,added the sodium hydroxide. Hydrothermal synthesis of reaction temperature is 170 ℃,reaction time is 18h,drying temperature is 80 ℃,drying time is 24h. By changing the ratio of nickel and urea was observed in the case of different proportions,Ni(OH)2 microspheres petal crystal structure,changes in particle morphology.Nickel nitrate and nickel source,ammonia as the precipitating agent,conduct crystal structure,comparison of different particle morphologies observed in different precipitant synthesized Ni(OH)2.
X-ray diffraction (XRD) and scanning electron microscopy (SEM) were carried out on the synthesis phase and morphology of the sample analysis results show that with the increase of urea molar ratio of nickel,Ni(OH)2 particle size decreases first and then increased petal structure becomes gradually clear,decreases the thickness of the petals,petals become loose. One of the best nickel and urea ratio of 1:5. Increasing Ni molar ratio in favor of the formation of urea,β-Ni(OH)2 in. Increasing the concentration of the nickel nitrate solution conducive to the formation of spherical nickel hydroxide. Urea precipitant than ammonia.
Key words: Nanomaterials ; nickel hydroxide; hydrothermal method; urea; ammonia
II
内蒙古科技大学本科生毕业论文
目 录
摘 要.............................................................................................................................. I Abstract ........................................................................................................................... II 目 录............................................................................................................................ III 第一章 引 言 ................................................................................................................ 1
1.1 镍氢电池的发展 ............................................................................................... 1 1.2 纳米材料及纳米氢氧化镍简介 ........................................................................ 3
1.2.1 纳米材料简介 ........................................................................................ 3 1.2.3 纳米氢氧化镍简介 ................................................................................ 4 1.3 MH-Ni电池充放电原理 .................................................................................... 6 1.4 氢氧化镍制备简介 ......................................................................................... 10
1.4.1 配位均匀沉淀法 .................................................................................. 10 1.4.2 均相沉淀法 .......................................................................................... 11 1.4.3 沉淀转换法 .......................................................................................... 12 1.4.4 水热法 .................................................................................................. 12 1.4.5 无水乙醇法 .......................................................................................... 13 1.4.6 反相胶束法（微乳液法） ................................................................... 14 1.4.7 溶胶—凝胶法 ...................................................................................... 14 1.4.8 物理法—高能球磨法 .......................................................................... 15 1.4.9 离子交换树脂法 .................................................................................. 16 1.4.10 低温固相反应法 ................................................................................ 16 1.4.11 醇盐电解法 ........................................................................................ 16
III
内蒙古科技大学本科生毕业论文
1.5 花瓣状Ni(OH)2 的形成机制 ......................................................................... 17 1.6 氢氧化镍结晶过程的影响因素 ...................................................................... 18
1.6.1 反应物料的影响 .................................................................................. 18 1.6.2 加料方式的影响 .................................................................................. 19 1.6.3 pH值的影响 ......................................................................................... 19 1.7 国内外研究现状 ............................................................................................. 20 1.8 文献总结 ......................................................................................................... 21 1.9 本文工作和实验方案 ..................................................................................... 22 1.10 研究目的及意义 ........................................................................................... 23 第二章 纳米Ni(OH)2的制备 ....................................................................................... 24
2.1 实验仪器及药品 ............................................................................................. 24
2.1.1 实验仪器 .............................................................................................. 24 2.1.2 药品 ...................................................................................................... 26 2.2 实验方案 ......................................................................................................... 26
2.2.1 实验工艺流程图 .................................................................................. 26 2.2.2 实验步骤 .............................................................................................. 27 2.2.3实验设计方案 ....................................................................................... 28 2.2.4 实验原理 .............................................................................................. 28
第三章 实验样品表征及结论 ...................................................................................... 30
3.1 XRD测试分析 ................................................................................................. 30
3.1.1 XRD简介 .............................................................................................. 30 3.1.2 XRD图像分析及结果 .......................................................................... 31
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