多层泡沫镍体系提高氢氧化镍纳米片电极的循环性能

发布时间：2018-06-17 23:20

本文选题：氢氧化镍 + 多层泡沫镍　；参考：《太原理工大学》2017年硕士论文

【摘要】：化石能源危机问题的日益突出以及由于大量使用化石燃料带来的越来越严重的环境问题给人类带来了极大的困扰,开发利用清洁可再生能源成为人类实现可持续发展的必要任务。但是新能源的高效利用离不开性能优异的储能器件,作为储能器件的超级电容器由于其环境友好、功率密度高、循环寿命长、使用温度范围宽等优点成了国内外广大研究者们的新宠。而开发高性能的超级电容器储能器件离不开设计制备性能优异的材料以及对电极材料的合理组装。以双电层电容为基础的碳材料超级电容器因其理论容量不高而发展受限,而过渡金属氢氧化物因其具有高的理论容量引发了研究者们的兴趣,其中氢氧化镍又以其廉价、无毒、环境友好等优点而备受青睐。然而,氢氧化镍属于半导体材料,较差的导电性导致了氢氧化镍电极材料较差的倍率性能和循环性能。在本论文中,我们通过简单的水热合成方法制备了不同纳米尺寸的片状氢氧化镍电极材料。为了提升氢氧化镍电极材料的循环性能,我们改善了电极的制备方法,将传统的单层泡沫镍体系扩展为多层泡沫镍体系(实际为4层泡沫镍)。本文的主要内容如下:1.以NiCl_2·6H_2O和NH_4(CO_3)_2为原料,利用水热合成的方法制备出了Ni(HCO_3)_2,将所得到的Ni(HCO_3)_2浸泡在6 M的KOH溶液中得到了尺寸约为14.5 nm的氢氧化镍纳米片。分别采取传统单层泡沫镍体系和多层泡沫镍体系制备出两个电极(N1和N3),电化学结果证实在5 A g~(-1)的电流密度下,N1和N3电极的容量分别为482.9和524.5 C g~(-1);经1000圈的循环过后,N1和N3电极的容量保持率分别为59.1%和83.8%。显然,多层泡沫镍体系大大提高了氢氧化镍纳米片电极的循环稳定性,并在此基础上提出了改良电极的工作机理,探究了其能提高电极材料循环性能的原因。2.以NiCl_2·6H_2O和Na_2CO_3为原料,利用水热合成的方法制备出了尺寸约为150 nm的片状氢氧化镍。分别采取传统单层泡沫镍体系和多层泡沫镍体系制备出两个电极(A1和A3),电化学结果证实在5 A g~(-1)的电流密度下,经1000圈的循环过后,两电极的容量保持率分别为42%和80%。显然,多层泡沫镍体系不仅适用于超小片状纳米体系的电极材料,还适用于其他大尺寸片状纳米体系的电极材料,具有一定的普遍性。
[Abstract]:The problem of fossil energy crisis is becoming more and more prominent, and the environmental problems caused by the heavy use of fossil fuels have brought great troubles to human beings. Development and utilization of clean and renewable energy has become a necessary task for human to achieve sustainable development. However, the efficient utilization of new energy can not be separated from energy storage devices with excellent performance. As energy storage devices, supercapacitors are environmentally friendly, have high power density, and have long cycle life. Using the advantages of wide temperature range has become a new favorite of researchers at home and abroad. The development of high performance supercapacitor energy storage devices can not be separated from the design of excellent materials and the reasonable assembly of electrode materials. The development of carbon supercapacitors based on double layer capacitors is limited because of their low theoretical capacity, while transition metal hydroxides have attracted the interest of researchers because of their high theoretical capacity. Among them, nickel hydroxide is cheap and non-toxic. Environmental friendly and other advantages are favored. However, nickel hydroxide is a semiconductor material. The poor conductivity leads to the poor performance of the nickel hydroxide electrode material. In this thesis, we prepared different nanoscale nickel hydroxide electrode materials by simple hydrothermal synthesis method. In order to improve the cycling performance of nickel hydroxide electrode materials, we have improved the preparation method of the electrode, and extended the traditional single-layer nickel foam system to a multi-layer nickel foam system (actually, four layers of nickel foam). The main contents of this paper are as follows: 1. NiHCO3s were prepared by hydrothermal synthesis from the NiCl26H _ 2O and NH _ 4C _ C _ 3s _ 2 as the raw materials. The NiHCO3T _ 2 was soaked in the 6M Koh solution to obtain the nickel hydroxide nanocrystals of about 14.5 nm. Two electrodes, N 1 and N 3, were prepared by conventional single layer nickel foam system and multilayer nickel foam system, respectively. The electrochemical results show that the capacities of N 1 and N 3 electrodes are 482.9 and 524.5 C / g ~ (-1) at the current density of 5 A g / g ~ (-1), respectively, and the results show that the N _ (1) and N _ (3) electrodes are cyclic in 1000 cycles. The capacity retention rates of N1 and N3 electrodes were 59.1% and 83.8%, respectively. It is obvious that the multilayer nickel foam system can greatly improve the cycling stability of nickel hydroxide nanocrystalline electrode. On this basis, the working mechanism of the modified electrode is put forward, and the reason why it can improve the cycling performance of the electrode material is explored. Using NiCl26H _ 2O and Na _ 2CO _ 3 as raw materials, the size of nickel hydroxide (150 nm) was prepared by hydrothermal synthesis. Two electrodes, Al and A3N, were prepared by conventional single layer nickel foam system and multilayer nickel foam system, respectively. The electrochemical results show that at the current density of 5 A g ~ (-1), after 1000 cycles, the capacity retention rates of the two electrodes are 42% and 80%, respectively. It is obvious that the multilayer nickel foam system is suitable not only for the electrode materials of ultrasmall sheet nanosystems, but also for the electrode materials of other large scale sheet nanosystems, which has a certain universality.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ138.13;TM53

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