纳米CoO/三维石墨烯复合材料在超级电容器中的应用

	纳米CoO/三维石墨烯复合材料在超级电容器中的应用
Alternative Title	Nano CoO/3D graphene composites for supercapacitors application
	邓伟
Thesis Advisor	兰伟
	2014-06-03
Degree Grantor	兰州大学
Place of Conferral	兰州
Degree Name	硕士
Keyword	超级电容器三维石墨烯 CoO纳米片 CoO纳米束循环伏安法恒电流充放电测试
Abstract	本论文以提高超级电容的比电容，倍率特性和循环稳定性为目的，设计和制备新的电极材料。首先，利用化学气相沉积法制备出自支撑的三维石墨烯材料。然后，通过水热法在其表面复合不同的CoO纳米结构，制备出高性能电极材料。本论文主要内容如下：（1）在泡沫镍表面生长出多层石墨烯，然后通过酸处理，制得自支撑的三维石墨烯结构。它具有多孔的结构，高的导电性，电化学稳定性和超轻的质量，是一种优良的超级电容器电极材料。（2）利用水热法和热处理过程，在石墨烯表面生长出多孔的CoO纳米片材料。CoO纳米片/三维石墨烯复合电极因剔除了非活性的粘结剂、导电添加剂等，获得了较高的比电容。在1A/g电流下比电容达231.87F/g，即使计入整个电极的质量，比电容仍可达139.47F/g。当电流密度从1A/g增大到10A/g时，比电容保持率达79%，证明了电极良好的倍率特性。通过1000次以上的循环测试，观察到比电容仅有不到2% 的衰减，表明电极具有高的循环稳定性。（3）通过改变水热反应物和条件，在三维石墨烯表面制备出新的CoO束状纳米材料。在1A/g电流下比电容达到352.75F/g，电流密度从1A/g增加到10A/g时比电容保持率超过88%，性能高于CoO纳米片材料。通过1000次以上循环测试显示比电容几乎没有衰减，表明优良的循环稳定性。
Other Abstract	To improve the specific capacitance, rate capability and cycling stability of supercapacitors, we engineered and prepared novel supercapacitor electrodes. First, the freestanding 3D graphene foams (GF) were prepared by chemical vapor deposition (CVD). Then the different CoO nanostructures were grown on the 3D GF forming composite materials to produce high performance electrodes materials. The main contents of this thesis are as follow: (1) Muti-layer graphenes were deposited on Ni foam. Subsequently the Ni foams coated with graphene were soaked in HCl to dissolve the Ni foams completely. Eventually, the freestanding 3D graphene foams were gained. The porous GFs with good electrical conductivity, electrochemical stability and ultra-light mass are excellent electrode materials for supercapacitors. (2) Porous CoO nanowalls were grown on graphene by a hydrothermal process and succedent annealing treatment. The CoO nanowalls/3D GF hybrid electrodes with ultra-light current collectors that eliminate the use of less active materials such as binder materials, conductive additives obtained a high specific capacitance. When the 1A/g current density was applied, capacitances of 231.87 F/g (139.47 F/g even scaled for total mass of electrode) were fulfilled. Even the charge-discharge current increases from 1 to 10 A/g, there is still ~79% remain of the capacitance. The cycling stability of the CoO@GF hybrid electrode was examined over 1000 cycles. The capacitance maintained is over 98% and without noticeable change of curves which reveals good cycling performance. (3) Novel CoO nanobundles materials were synthesized on the surface of 3D graphene through altering reactants and conditions of hydrothermal reactions. Capacitances of 231.87 F/g (scaled for total mass of CoO) were fulfilled at 1A/g current density. When the charge-discharge current increases from 1 to 10 A/g, the remain of the capacitance exceed 88%. The CoO NB@GFs hybrid electrodes were charge/discharge over 1000 cycles with nearly no attenuation of specific capacitances which improves excellent cycling performance.
URL	查看原文
Language	中文
Document Type	学位论文
Identifier	https://ir.lzu.edu.cn/handle/262010/229556
Collection	物理科学与技术学院
Recommended Citation GB/T 7714	邓伟. 纳米CoO/三维石墨烯复合材料在超级电容器中的应用[D]. 兰州. 兰州大学,2014.

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