锰酸镍@石墨化碳片复合结构阵列的设计合成及其在储能器件的应用

发布时间：2018-03-05 05:24

本文选题：三明治　切入点：石墨化碳　出处：《重庆大学》2016年硕士论文　论文类型：学位论文

【摘要】：超级电容器(SCs)和锂离子电池(LIBs)是很有发展潜力的储能装置,因其具有能量密度高、寿命长、环境友好、安全等优点倍受人们关注。目前超级电容器和锂离子电池已经广泛用于便携式电子设备中,比如笔记本电脑、手机、摄像机、遥控器等电子产品。由于纳米材料的特殊性能及其在众多领域的广泛应用,尤其是在生物医学、与能源相关以及电子领域中,选择性合成纳米材料变得越来越重要。而合成纳米材料的一种有效方法是结合活性材料与辅助材料制备功能体系。对于活性材料,过渡金属氧化物则是最有前景的活性材料之一,因为它在光学、磁学、催化剂、电学领域有其独特性能,特别是在电化学能量储存领域。本文首次合成了新型镍锰氧化物@石墨化碳片三明治复合结构阵列,其作为超级电容器和锂离子电池材料展示了优良的性能。本文以超薄的层状双氢氧化物(NiMn-LDH)纳米片作为前驱物和牺牲模板,葡萄糖分子作为绿色碳源。而葡萄糖碳源首先通过水热反应,再和前驱物的氢键作用下,转变成了聚合层,然后在惰性气体下高温煅烧转变成了石墨化碳片,与此同时,NiMn-LDH纳米片在高温与碳片的作用下经过分解和还原反应转化成镍锰合金纳米颗粒包覆在碳片中。最后,样品在空气中高温煅烧200分钟,使镍锰合金纳米颗粒转化成NiMn2O4纳米颗粒包覆在碳片中。由于本文合成的三明治复合材料有效地结合了NiMn2O4功能纳米颗粒和石墨化碳片的优势,因而其在电化学能量存储方面具有协同作用。其作为超级电容器和锂离子电池材料呈现出优良的电化学性能,尤其体现在大电流充放电性能,循环性及使用寿命上。实验通过采用XRD、EDS、TEM、SEM、BET及电化学测试来表征、分析所合成的三明治状复合材料的形态及性能。本实验合成的三明治状复合材料由于有石墨化碳层和导电基底,使其不仅可以提高电导率,还能有效防止纳米粒子的团聚和活性材料的坍塌,是优良的储能材料。其作为超级电容器的电极材料,在电流密度为1 A/g时,比电容量高达2679 F/g,经过6000次循环以后,比容量还能保持98%以上。其作为锂离子电池负极材料,在电流密度为500mA/g时,首次循环的比容量高达1346 mAh/g,在200次循环内,其库伦效率接近100%。
[Abstract]:Supercapacitor SCsand lithium-ion battery (Li-ion battery) are potential energy storage devices, because of their high energy density, long life, environmentally friendly, Security has attracted much attention. Supercapacitors and lithium-ion batteries have been widely used in portable electronic devices, such as laptops, mobile phones, cameras, Electronic products such as remote controls. Because of the special properties of nanomaterials and their wide applications in many fields, especially in biomedical, energy-related and electronic fields, The selective synthesis of nanomaterials has become more and more important. An effective way to synthesize nanomaterials is to combine active materials with auxiliary materials to prepare functional systems. Transition metal oxides are one of the most promising active materials because they have unique properties in the fields of optics, magnetism, catalyst and electricity. Especially in the field of electrochemical energy storage, a novel nickel-manganese oxide @ graphitized carbon sandwich sandwich composite array was synthesized for the first time. The supercapacitors and lithium-ion batteries exhibit excellent properties. In this paper, ultrathin layered NiMn-LDHs are used as precursors and sacrificial templates. The glucose molecule is used as a green carbon source, and the glucose carbon source is converted into a polymeric layer by hydrothermal reaction, then by hydrogen bonding with the precursor, and then calcined into a graphitized carbon sheet at high temperature in inert gas. At the same time, NiMn-LDH nanoparticles were decomposed and reduced to Ni-Mn alloy nanoparticles coated in carbon sheets at high temperature. Finally, the samples were calcined in air for 200 minutes at high temperature. Nickel-manganese alloy nanoparticles were transformed into NiMn2O4 nanoparticles and coated in carbon sheets. Because the sandwich composites synthesized in this paper effectively combined the advantages of NiMn2O4 functional nanoparticles and graphitized carbon sheets, Therefore, it has synergistic effect on electrochemical energy storage. It has excellent electrochemical performance as supercapacitors and lithium-ion battery materials, especially in high current charge-discharge performance. The morphology and properties of the sandwich composites were characterized by XRDX EDSTEMSEMET and electrochemical tests. The sandwich composites were prepared by graphite carbon layer and conductive substrate. It can not only improve the conductivity, but also prevent the agglomeration of nanoparticles and the collapse of active materials. It is an excellent energy storage material. As an electrode material for supercapacitors, when the current density is 1 / g, The specific capacitance is as high as 2679F / g, and after 6, 000 cycles, the specific capacity can be kept above 98%. As a cathode material for lithium ion batteries, the first cycle has a specific capacity of 1346 mAh/ g at 500mAr / g current density, and its Coulomb efficiency is close to 100mAh/ g in 200th cycle.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TB33

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