多元纳米多孔复合电极的制备与性能研究

发布时间：2018-11-09 15:08

【摘要】：超级电容器因为具有高功率密度,充放电速度快,循环使用寿命长,绿色安全等优点受到研究学者的广泛关注。基于过渡族金属氧化物的赝电容器电极材料因为具有高的能量密度成为一种非常具有应用前景的电容器电极材料,但是金属氧化物因为导电性差成为其制约因素。当前许多研究通过添加导电增强体可制备出纳米结构材料来提高金属氧化物的导电性,但是采用此种方法同样因为界面结合力差以及活性物质负载不均匀而影响其性能。通过在纳米多孔金属表面自生长一层氧化物可有效解决导电性差以及界面结合力差的缺点,本论文在二元NiMn、二元NiCuMn的基础上通过引入具有高稳定性、高理论比电容的钴氧化物成功制备出具有高电位窗口,高体积比电容的新型NiCoMn三元复合电极,同时考虑引入价格低廉的铁、铜对不同体系进行电化学综合性能研究。研究主要内容为：(1)根据相图制备出不同体系的厚度为25um的合金条带。EDX及XRD表征表明合金条带成分均匀属于单相固溶体,有利于形成孔径分布均匀的三维纳米多孔结构。(2)采用脱合金化法成功制备出孔径分布均匀的纳米多孔合金。XPS表征显示不同体系中金属元素均存在不同价态或者轨道的金属阳离子,且分析氧元素也存在三种结合形式,其中金属氧化物和氢氧化物的含量高有利于提高电化学性能。BET分析,其孔径分布均为1～10nm之间,比表面积以Ni20C10Mn70电极最大为48m2/g有利于负载更多的活性物质。TEM分析其孔径分布与BET测试一致,对不同衍射斑点分析纳米多孔金属氧化物电极存在两种不同的相。(3)对不同体系进行电化学性能测试发现,NiFeMn体系因为Fe和Cu的理论比电容低很难得到高比电容的电极材料,但是其体积比电容高达921F/cm~3。而对不同成分的NiCoMn体系研究发现,合金体系为Ni20Co10Mn70制备的电极电化学性能最优,在有效工作电位窗口为1.5V下,比电容高达2012F/cm~3,其能量密度高达114mWh/cm~3,高于当前实际应用电容器近5倍以上,两电极测试结果与三电极性能相近。
[Abstract]:Because of its high power density, high charge and discharge speed, long cycle life and green safety, supercapacitors have attracted much attention. Due to its high energy density, pseudo-capacitor electrode materials based on transition metal oxides have become a promising electrode material for capacitors, but metal oxides have become the limiting factors because of their poor conductivity. At present, many researches can improve the electrical conductivity of metal oxides by adding conductive reinforcements. However, this method also affects the properties of metal oxides because of poor interfacial adhesion and uneven loading of active substances. By self-growing a layer of oxide on the surface of nano-porous metal, the shortcomings of poor electrical conductivity and poor interfacial adhesion can be effectively solved. In this paper, the introduction of binary NiMn, binary NiCuMn has high stability. A novel NiCoMn ternary composite electrode with high potential window and high volume specific capacitance was successfully prepared by cobalt oxide with high theoretical specific capacitance. At the same time, the electrochemical comprehensive properties of different systems were studied by introducing low-cost iron and copper. The main contents of the study are as follows: (1) the alloy strips with different 25um thickness have been prepared according to the phase diagram. The results of EDX and XRD show that the alloy bands are homogeneous single-phase solid solution. (2) Nano-porous alloy with uniform pore size distribution was successfully prepared by dealloying method. XPS characterization showed that there were different valence of metal elements in different systems. Metal cations in states or orbits, There are also three kinds of binding forms for the analysis of oxygen elements, among which the high content of metal oxides and hydroxides is beneficial to the improvement of electrochemical performance. The pore size distribution in BET analysis is between 1~10nm and hydroxide. The maximum specific surface area of Ni20C10Mn70 electrode for 48m2/g is favorable for loading more active substances. The pore size distribution of TEM is consistent with that of BET. Different diffraction spots were used to analyze the existence of two different phases in nano-porous metal oxide electrodes. (3) the electrochemical properties of different systems were tested. It is difficult to obtain high specific capacitance electrode material in NiFeMn system because the theory of Fe and Cu is lower than that of capacitance, but its volume specific capacitance is as high as 921 F / cm ~ (3). On the other hand, the electrochemical properties of the electrode prepared by Ni20Co10Mn70 were found to be the best in the NiCoMn system with different composition. The specific capacitance of the electrode was up to 2012F / cm ~ (-1) and the energy density of the electrode was up to 114mWh/ cm ~ (3) under the effective working potential window of 1.5 V. The performance of the two electrodes is similar to that of the three electrodes.
【学位授予单位】：天津工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TB383.1;TM53

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