掺杂NiO纳米空心管制备及电化学性能研究

发布时间：2018-04-06 05:35

本文选题：超级电容器　切入点：静电纺丝　出处：《电子科技大学》2015年硕士论文

【摘要】：超级电容器,它是一种用于储能的元件,其原理基于电极/溶液界面的电化学过程。它既有可以和电池相比拟的储能能力,又有像静电电容器一样的大的放电功率。因为其众多的突出的优点,使其不可避免的成为了世界各国重点关注和研究的热点。其中电极材料是影响超级电容器的一个重要因素。由于氧化镍(Ni O)对环境友好、成本低廉、易合成,最重要的是,NiO具有很高的理论比电容2584F/g,这些优点使NiO成为一种最可能实际应用的理想电极材料,也因此受到研究者们的极大的关注。氧化镍的导电性能比较差,在电解液中离子的迁移速度慢,导致它的利用率不高。因此本文用静电纺丝的方法来制备掺入良好导电性物质的NiO纳米空心管,以提高其比表面积和导电性,进而提高所制备电极的电化学性能。采用静电纺丝的方法,制备具有空心结构的镧掺杂Ni O电极,其掺杂比例为La:Ni=0:1,1:1,1:2,1:4(摩尔比)。制得的电极在7mol/L KOH电解液中进行电化学性能测试,其中发现当La:Ni=1:2时,为最佳的比例,电化学性能最好。当以物质的全部质量来算,在电流密度为0.5A/g时,其容量有257.8 F/g,如果仅仅计算NiO的质量,其容量可以高达942 F/g,比纯的NiO的电容量高了14倍。在经过1000次的充放电测试后,容量仍然能保持在90%左右,有良好的循环稳定性。利用静电纺丝的制备工艺,用Ag对NiO进行掺杂,掺杂的量为AgNO3:镍盐=1%,2.5%,5%,10%(质量比),制备得到有高比表面积的空心纳米纤维。分别系统的对它们的形貌、晶型、比表面积及孔径等进行了分析。在7mol/L KOH电解液中对其电化学性能进行测试,发现掺杂比为5%时,电化学性能最好,在电流密度为0.5A/g时,其电容量可以达到200 F/g;在经历了1000次的充放电测试之后,电极的电容量的保持率可以达到95.6%;导电性能好,其法拉第电阻为2.59?。根据前两部分实验得出的结果,采用静电纺丝的方法对不同比例的银掺杂NiO/LaNiO3(La:Ni=1:2)的电极进行制备。其掺杂的比例为硝酸银:(硝酸镍+硝酸镧)=1%,2.5%,5%,10%。改变银掺杂的比例,可得到不同含量的复合纳米纤维。在7mol/L KOH电解液中对其电化学性能进行测试,其中发现5%为最佳的比例,电化学性能最好并且也优于前面的两种实验方法。其容量可以达到385.7 F/g在电流密度为1A/g的情况下;在进行1000次的恒流充放电之后,其电容量的保持率可以达到97%;导电性能也得到较大的提高,其法拉第电阻为0.79?。
[Abstract]:Super capacitor, it is used as a storage element, the principle of electrochemical process of electrode / solution interface. It can be based on comparable and battery energy storage capacity, and the discharge power of electrostatic capacitors as well. Because of its many advantages, which can not be avoided the world has become a hot focus of attention and study. The electrode material is an important factor affecting the super capacitor. The nickel oxide (Ni O) is friendly to the environment, low cost, easy synthesis, the most important is that NiO has very high theoretical specific capacitance of 2584F/ g, these advantages make NiO become one of the most possible ideal electrode materials for practical application, therefore because of their great attention. The conductive properties of nickel oxide is relatively poor, the migration velocity of ions in the electrolyte is slow, leading to its utilization rate is not high. So this method for electrostatic spinning NiO hollow nano preparation doped with good conductive materials, in order to improve its surface area and conductivity, and improve the electrochemical performance of the prepared electrode. Using electrospinning method, preparation of lanthanum doped Ni O electrode hollow structure, the doping ratio of La:Ni=0:1,1: 1,1:2,1:4 (molar ratio) electrode. Prepared by electrochemical performance test in 7mol/L KOH electrolyte, which found that when La:Ni=1:2, the best proportion, the best electrochemical performance. When to count all the quality of material, the cathodic current density was 0.5A/g, its capacity is 257.8 F/g, only if the quality NiO calculation, the capacity can be up to 942 F/g the specific capacitance, pure NiO high 14 times. After the charge discharge tests after 1000 times, the capacity can still be maintained at around 90%, has good cycle stability. The preparation process of electrospinning of NiO by doping with Ag doping. The amount of AgNO3: nickel salt =1%, 2.5%, 5%, 10% (mass ratio), the prepared hollow nano fiber with high specific surface area. Respectively on their morphology, crystal type, analysis of the specific surface area and pore size. The electrochemical tests in 7mol/L KOH electrolyte, found the doping ratio is 5%, the best electrochemical performance, the current density is 0.5A/g, the capacitance can reach 200 F/g; after 1000 charge discharge test, capacitance electrode retention rate can reach 95.6%; good conductivity, the resistance of Faraday was 2.59?. according to the two part of the experiment the results of method by electrospinning of silver doped NiO/LaNiO3 in different proportion (La:Ni=1:2) electrode was prepared. The doping ratio of silver nitrate: (nickel nitrate + lanthanum nitrate) =1%, 2.5%, 5%, 10%. change of silver doped proportion of nano composite can get different content Fiber. The electrochemical tests in 7mol/L KOH electrolyte, which found that 5% is the best proportion of two kinds of experimental methods and the best electrochemical performance is better than the front. The capacity can reach 385.7 F/g at the current density of 1A/g; in 1000 the constant current charge discharge, the capacitance the retention rate can reach 97%; the conductive performance is greatly improved, the Faraday resistance is 0.79?.

【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ138.13;TB383.1

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