钠离子储能电池碳基负极材料研究

发布时间：2018-01-14 08:21

本文关键词：钠离子储能电池碳基负极材料研究　出处：《中国科学院大学(中国科学院物理研究所)》2017年博士论文　论文类型：学位论文

【摘要】：随着化石燃料的耗竭和环境污染问题的加剧,风能、太阳能等可再生清洁能源的利用越来越受到人们的重视,但是这些可再生能源受自然环境的影响具有波动性和间歇性,难以实现对电网进行稳定的输出,储能系统对于实现可再生能源的高效利用至关重要。在众多的储能技术中,锂离子电池由于具有高能量密度、高的功率密度、长循环寿命等优点已经全面占领了便携电子设备和新能源电动汽车的市场。但是锂的储量有限、并且分布不均匀,限制了锂离子电池在储能上的大规模应用。与锂具有相似物理化学性质的钠却储量丰富、分布广泛并且成本低廉,使得钠离子电池在大规模电网储能上具有广泛的应用前景。但缺少合适的负极材料限制了钠离子电池的商业化应用。基于此背景,本论文开发研究了三类钠离子电池碳基负极材料:第一类为生物质基硬碳负极材料,第二类为沥青基非晶碳负极材料,第三类为裂解无烟煤负极材料。(1)硬碳由于具有高的比容量、低的储钠电位和好的循环稳定性而受到科研工作者的广泛研究。本文第一部分分别利用蔗糖和棉花作为前驱体,得到了形状规则的硬碳球和硬碳微米管两种材料,并首次系统研究了碳化温度对于硬碳微结构以及储钠性能的影响。研究表明钠离子嵌入硬碳过程具有较差的动力学性能,利用GITT手段进一步澄清了电化学曲线平台部分低的钠离子扩散系数是限制硬碳倍率性能的原因,非原位TEM和XPS结果证明了斜坡部分对应钠离子在缺陷和表面位置的吸附与平台部分对应钠离子在纳米空穴中存储的储钠机制。(2)虽然硬碳表现优异的储钠性能,但是较高的成本限制了其应用。本文第二部分通过利用在沥青中加入第二相的方法,提高了沥青裂解碳的无定型度,实现了在制备钠离子电池非晶碳负极材料上的应用。首先通过在沥青中加入硬碳前驱体第二相的方法,提高其无定型度和储钠性能,取得了很好的效果。沥青与酚醛树脂复合碳材料展现了高达284 mAh/g的储钠容量。为了进一步降低成本,我们接下来将硬碳前驱体换为自然界中含量第二丰富的木质素,并且发现了木质素对沥青有乳化作用,其复合碳材料具有259mAh/g的储钠容量和较低的价格。最后,利用KOH作为活化剂对沥青进行活化处理得到了具有288mAh/g储钠容量的非晶碳材料,并且KOH可以进行回收重复利用,是一种活化沥青制备非晶碳材料的理想活化剂。所有负极材料的应用前景都在以Na0.9[Cu0.22Fe0.30Mn0.48]O2为正极材料的扣式全电池得以验证。(3)为了进一步简化制备过程,得到成本更加低廉的负极材料,我们选用了自然界中含量丰富、价格低廉的无烟煤作为前驱体,通过简单的一步碳化方法得到了一种性能优异的软碳负极材料,其在目前报道的所有的负极材料中展现了最高的性价比。该裂解无烟煤材料的应用前景也在以其为负极和Na0.9[Cu0.22Fe0.30Mn0.48]O2为正极的软包电池所展示,该软包电池展现了100Wh/kg的实际能量密度、优异的倍率和循环性能,更重要的是该软包电池在针刺、过充和短路等一系列的安全测试中表现出优异的安全性能。我们也利用原位XRD和非原位的XPS等手段证明了其与硬碳相同的储钠机制。
[Abstract]:With the depletion of fossil fuel and environmental pollution intensifies, the use of wind, solar and other renewable clean energy more and more attention, but these renewable energy affected by natural environment is fluctuant and intermittent, difficult to achieve stable output of power grid, energy storage system to realize the essential for the efficient use of renewable energy in many of the energy storage technology, lithium ion batteries because of its high energy density, high power density, long cycle life and other advantages have been fully occupied by the portable electronic equipment and new energy electric vehicle market. But lithium reserves are limited, and the distribution is not uniform, limiting the lithium ion battery in large-scale energy storage applications the similar physical and chemical properties of lithium and sodium has abundant reserves, wide distribution and low cost, the sodium ion battery in large scale power grid storage Has a wide application prospect can. But the lack of commercial application of proper anode materials limits the sodium ion battery. Based on this background, this paper developed three kinds of sodium ion battery carbon based anode materials: the first type is hard carbon anode materials for asphalt second kinds of biomass based, amorphous carbon anode materials, third as anode materials for anthracite pyrolysis. (1) hard carbon due to its high specific capacity, cycling stability and low sodium storage potential and widely researched by scientists. In the first part of this paper respectively using sugar and cotton as the precursor, the hard carbon ball shape rules and hard carbon microtubes of two kinds of materials that is the first systematic study of the carbonization temperature on the microstructure and the hard carbon storage effect. The results show that the performance of sodium dynamics performance of sodium ion embedded hard carbon process is poor, further clarify the power by means of GITT The chemical part of low sodium curve platform ion diffusion coefficient is the performance limiting carbon ratio, in situ TEM and XPS results show that the storage mechanism of sodium sodium ion in the corresponding part of the slope and the corresponding part of the sodium ion adsorption platform defects and surface position in nano hole in storage. (2) although the hard carbon storage of sodium with excellent performance, but the high cost limits its application. The second part of this paper by using the method of adding the second phase in asphalt, asphalt increased pyrolytic carbon amorphous, the preparation of sodium ion battery application of amorphous carbon anode materials in the system. First, through the method of adding hard carbon precursors in the second phase in asphalt, improve the amorphous degree and sodium storage performance, and achieved good results. Asphalt and phenolic resin composite carbon materials show the sodium storage capacity of up to 284 mAh/g. In order to further reduce the cost, we meet It will be hard for the carbon precursor wood in nature the second most abundant element, and found that the lignin of emulsified asphalt, the storage capacity of sodium carbon composite materials with 259mAh/g and low price. Finally, using KOH as the activating agent on asphalt were activated by amorphous carbon material has 288mAh/g sodium storage capacity, and KOH can be recycled, is a kind of activated asphalt preparation of amorphous carbon material ideal activator. The application prospects of all anode materials are verified in the Na0.9[Cu0.22Fe0.30Mn0.48]O2 button for full battery cathode materials. (3) in order to further simplify the preparation process, get the cost the more cheap anode materials, we choose the abundant in nature, low price of anthracite as precursor by one-step carbonization method is simple and has soft carbon anode excellent properties The material, showing the highest price in all of the anode materials reported. The application prospect of this material in cracking anthracite as the anode and Na0.9[Cu0.22Fe0.30Mn0.48]O2 display for soft battery cathode, the pouch cell exhibits the actual energy density 100Wh/kg, excellent rate and cycle performance, and it is more important pouch cells in acupuncture, showed excellent safety performance of overcharge and short-circuit and a series of safety tests. We also use the in situ XRD and ex situ XPS method proved that the same hard carbon and sodium storage mechanism.

【学位授予单位】：中国科学院大学(中国科学院物理研究所)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TM912

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