绿色能源材料钛酸锂的改性及其回收再利用的研究
发布时间：2018-08-08 12:39
【摘要】：能源与环境是相互关联的二元体系,能源消耗与环境污染并存,能源短缺制约社会发展。随着人们对石油价格升高和日益严峻的环境问题的关注,发展绿色能源成为当今能源社会的热点。为了充分利用风能、太阳能等清洁能源,常用铅酸电池作为储能电源。但铅酸电池在回收利用过程中由于铅泄露而造成严重的环境污染,给人们的健康带来很大的危害。锂离子电池不含有害物质,是绿色环保电源,可以应用于电动汽车和储能系统,有利于节能减排及缓解二氧化碳排放所造成的温室气体效应。与其他的化学电源相比,锂离子电池具有较高的能量密度和较长的循环寿命,在可携带式电子设备上得到广泛的应用。钛酸锂(LTO)被认为是一种可取代传统碳材料的锂离子电池负极材料。由于LTO具有丰富的二氧化钛原料来源、优异的循环可逆性和稳定性、相对较高的容量(175 mAh-g-1)及安全性能较好等优点,它成为应用于下一代动力锂离子电池的重要的负极材料。LTO在充放电过程中零应变体积及在1.55 V的高锂插入电压平台,可有效地防止金属锂的形成,从而可以提高锂离子电池的安全性。但是,LTO负极材料在大功率电池上的应用受到其自身电子电导率差的制约。掺杂已被证明是提高其电子电导率的一种有效途径,因此,在本论文中,我们通过掺杂一些金属离子如Ca2+、W6+、Gd3+和Nd3+等提高LTO的高倍率性能。首先,我们采用Ca2+作掺杂离子来提高LTO的电导率。Li4-xCaxTi5O12 (x=0,0.05,0.1,0.15,0.2)形式的Ca掺杂LTO负极材料用一种简易的固相反应法合成。XRD结果表明,Ca掺杂没有造成晶格结构的改变,并且得到了没有杂质的高纯相的Li4-xCaxTisO12 (0≤x≤0.2)颗粒。SEM图像显示,所制备的粉末有相似的颗粒相貌,颗粒尺寸分布在1-2 μm之间。在制备的所有样品中,L13.9Ca0.1Ti5O12表现出较高的比容量、较好的循环及倍率性能。在1C、5C和10C充放电倍率下经过100次循环后,L13.9Ca0.1Ti5O12材料的放电容量分别为162.4 mA·hg-、148.8 mAh·g-1和138.7 mAh·g-1。为了进一步提高Li3.9Ca0.1Ti5O12(简写为LCTO)电极材料的能量密度,将电池放电至0V截止电压,LTO和LCTO通过固相反应法合成。XRD结果表明,用这种方法制备的颗粒是没有其他任何杂质的高纯相。LCTO比LTO表现出较高的放电比容量和较好的循环稳定性。当放电至0V时,在1C倍率下经过200次循环后,LCTO的容量仍高达240 mAh·g-1,比LTO高许多(仅为127.3 mAh·g-1)。同时,对两者在0-2.5 V电压范围内的电化学性能也进行了研究,并对放电至OV时Ca掺杂对提高LTO的能量密度的影响进行了讨论。接着,我们选用W6+作为掺杂离子来提高LTO的倍率性能。分别在空气和氩气气氛下利用溶胶-凝胶法和之后的两步煅烧法制备Li4Ti5-xWxO12(x=0.05,0.1,0.15,0.2)形式的W掺杂LTO样品。可以看出,W掺杂LTO样品比纯LTO样品的晶胞参数稍高些,W掺杂不改变LTO的立方尖晶石型结构。W掺杂LTO作为锂离子电池的负极材料表现出优异的电化学性能,样品Li4Ti4.9W0.1O1 2具有最好的倍率特性及循环稳定性。当在1C、5C和10C充放电倍率下,其第100次循环时的放电容量分别为162.5 mAh·g-1、145mAh·g-1和128.1 mAh·g-1。Gd3+作为锂离子电池正极材料的掺杂离子可以显著地提高其倍率性能,但是,在尖晶石型LTO负极材料中的掺杂效果至今还未作详细报道。Li4Ti5-XGdxO12(x=0.05,0.10,0.15)样品采用简单的固相反应法在空气气氛下制备。XRD结果表明,只有少量的掺杂离子进入了LTO的晶格结构中,多余的部分以Gd203杂质的形式存在,Gd掺杂不改变LTO的尖晶石型结构及电化学反应过程。所制备样品的颗粒尺寸范围为0.5-1.5μm。与未掺杂的LTO相比,Gd掺杂的LTO材料的倍率性能和比容量得到较大程度的提高。特别是Li4Ti4.95Gd0.05O12,它在所有样品中表现出最好的倍率性能和循环稳定性。但是,LTO中过多的Gd203杂质不利于其电化学性能的发挥。另外,用低价态的Nd3+离子掺杂LiMn2O4可以产生氧离子空位,从而以离子载体的形式大大提高LiMn2O4的电子电导率。受此研究启发,我们又采用溶胶-凝胶法合成了Nd掺杂LTO样品,并对所制备粉末的结构和电化学性能进行了系统地研究。即使在10C的高倍率下,L14Ti4.98Nd0.02O12仍表现出优异的倍率性能和循环稳定性。Ca2+、W6+、Gd3+和Nd3+四种金属离子的掺杂样品显著提高了锂离子电池的高倍率性能,可用于电动车的动力电池或风能、太阳能的储能系统装置中,有利于环境保护和节能减排,具有很广阔的应用前景。此外,我们利用有机溶剂法回收了上述使用过的废旧锂离子电池,并对回收产物进行了结构、形貌和性能测试。结果表明,最终回收的LTO电极材料表现出优异的循环稳定性和可逆性,可以循环利用。
[Abstract]:Energy and environment are interrelated two yuan system, energy consumption and environmental pollution coexist, energy shortage restricts social development. As people pay more attention to oil prices and increasingly severe environmental problems, the development of green energy has become a hot spot in today's energy society. In order to make full use of wind energy, solar energy and other clean energy, common lead acid is used. Batteries are used as energy storage power sources. But lead acid batteries cause serious environmental pollution caused by lead leakage in the recycling process. Lithium ion batteries do not contain harmful substances. It is a green and environmental protection power source. It can be applied to electric vehicles and energy storage systems. It is beneficial to energy saving and emission reduction and carbon dioxide emission reduction. Compared with other chemical sources, lithium ion batteries have high energy density and longer cycle life, and are widely used in portable electronic devices. Lithium titanate (LTO) is considered to be a kind of lithium ion battery anode material which can replace traditional carbon materials. Because of the rich two oxygen of LTO Titanium material source, excellent cyclic reversibility and stability, relatively high capacity (175 mAh-g-1) and good safety performance, it has become an important anode material for the next generation of power lithium ion batteries,.LTO, the zero strain volume in the charge discharge process and the high lithium insertion voltage platform at 1.55 V, can effectively prevent metal from the metal. The formation of lithium can improve the safety of lithium ion batteries. However, the application of LTO anode materials on high-power batteries is restricted by their own electronic conductivity. Doping has been proved to be an effective way to improve its electronic conductivity. Therefore, in this paper, we have doped some metal ions such as Ca2+, W6+, Gd3+, and so on. Nd3+ and so on improve the high performance of LTO. First, we use Ca2+ as doping ion to improve the.Li4-xCaxTi5O12 (x=0,0.05,0.1,0.15,0.2) form of.Li4-xCaxTi5O12 (x=0,0.05,0.1,0.15,0.2) in the form of Ca doped LTO negative material. A simple solid state reaction method is used to synthesize.XRD results. The result shows that Ca doping does not cause the change of the lattice structure, and the high degree of impurity is obtained. The pure phase Li4-xCaxTisO12 (0 < < x < < 0.2) particle.SEM image shows that the prepared powders have similar particle appearance and the particle size distribution is between 1-2 m. In all the samples prepared, L13.9Ca0.1Ti5O12 shows higher specific capacity, better circulation and multiplying performance. After 100 cycles under 1C, 5C and 10C charge and discharge ratio, L13. The discharge capacity of 9Ca0.1Ti5O12 materials is 162.4 mA. Hg-, 148.8 mAh. G-1 and 138.7 mAh. G-1. to further improve the energy density of Li3.9Ca0.1Ti5O12 (abbreviated LCTO) electrode material, discharge the battery to the 0V cut-off voltage, LTO and LCTO through the solid-phase reaction method, indicating that the particles prepared by this method are not. The high pure phase.LCTO of any of his impurities showed higher discharge ratio and better cyclic stability than LTO. When the discharge to 0V, after 200 cycles under 1C multiplying, the capacity of LCTO was still up to 240 mAh. G-1, much higher than LTO (127.3 mAh g-1). Meanwhile, the electrochemical performance of both in the 0-2.5 V voltage range was also carried out. The effect of Ca doping on increasing the energy density of LTO was discussed at OV. Then, we selected W6+ as doping ion to improve the ratio of LTO. In air and argon atmosphere, the Li4Ti5-xWxO12 (x=0.05,0.1,0.15,0.2) form of W doped LTO sample was prepared by the sol-gel method and the following two step calcination method. It can be seen that the W doped LTO sample is slightly higher than the crystal cell parameters of the pure LTO sample. The W doped cubic spinel type structure.W doped LTO has excellent electrochemical performance as the anode material of the lithium ion battery, and the sample Li4Ti4.9W0.1O1 2 has the best multiplier and cyclic stability. When 1C, 5C and 10C charge and discharge times At the rate of 100th cycles, the discharge capacity of 162.5 mAh. G-1 and 128.1 mAh. G-1.Gd3+ as the cathode material of the lithium ion battery can significantly improve its ratio performance. However, the doping effect in the spinel LTO negative electrode has not been reported in detail yet,.Li4Ti5-XGdxO12 (x=0.05,0.10,0.15). The sample prepared by a simple solid state reaction method in the air atmosphere.XRD results showed that only a small amount of doped ions entered the lattice structure of LTO, the excess part existed in the form of Gd203 impurities, Gd doping did not change the spinel structure of LTO and the electrochemical reaction process. The size range of the prepared sample was 0.5-1.5 mu m. Compared with the undoped LTO, the multiplier performance and specific capacity of the Gd doped LTO materials are greatly improved. Especially Li4Ti4.95Gd0.05O12, it shows the best ratio and cyclic stability in all samples. However, excessive Gd203 impurities in LTO are not conducive to the exertion of its electrical properties. In addition, the low-priced Nd3+ is used. The doping of LiMn2O4 can produce oxygen ion vacancies, thus greatly improving the electronic conductivity of LiMn2O4 in the form of ionophore. Inspired by this study, we have synthesized the Nd doped LTO samples by sol-gel method, and systematically studied the structure and electrochemical properties of the prepared powders. Even at the high rate of 10C, L14Ti4.98 Nd0.02O12 still shows excellent multiplier performance and cyclic stability.Ca2+, W6+, Gd3+ and Nd3+ doped samples of four metal ions significantly improve the high rate performance of lithium ion batteries, can be used in electric batteries or wind energy, solar energy storage system devices, is conducive to environmental protection and energy conservation and emission reduction, has a very broad need. In addition, the waste lithium ion batteries used above were recovered by organic solvent method and the structure, morphology and properties of the recovered products were tested. The results showed that the final recycled LTO electrode materials showed excellent cyclic stability and reversibility and could be recycled.
【学位授予单位】：复旦大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM912
本文编号：2171811
[Abstract]:Energy and environment are interrelated two yuan system, energy consumption and environmental pollution coexist, energy shortage restricts social development. As people pay more attention to oil prices and increasingly severe environmental problems, the development of green energy has become a hot spot in today's energy society. In order to make full use of wind energy, solar energy and other clean energy, common lead acid is used. Batteries are used as energy storage power sources. But lead acid batteries cause serious environmental pollution caused by lead leakage in the recycling process. Lithium ion batteries do not contain harmful substances. It is a green and environmental protection power source. It can be applied to electric vehicles and energy storage systems. It is beneficial to energy saving and emission reduction and carbon dioxide emission reduction. Compared with other chemical sources, lithium ion batteries have high energy density and longer cycle life, and are widely used in portable electronic devices. Lithium titanate (LTO) is considered to be a kind of lithium ion battery anode material which can replace traditional carbon materials. Because of the rich two oxygen of LTO Titanium material source, excellent cyclic reversibility and stability, relatively high capacity (175 mAh-g-1) and good safety performance, it has become an important anode material for the next generation of power lithium ion batteries,.LTO, the zero strain volume in the charge discharge process and the high lithium insertion voltage platform at 1.55 V, can effectively prevent metal from the metal. The formation of lithium can improve the safety of lithium ion batteries. However, the application of LTO anode materials on high-power batteries is restricted by their own electronic conductivity. Doping has been proved to be an effective way to improve its electronic conductivity. Therefore, in this paper, we have doped some metal ions such as Ca2+, W6+, Gd3+, and so on. Nd3+ and so on improve the high performance of LTO. First, we use Ca2+ as doping ion to improve the.Li4-xCaxTi5O12 (x=0,0.05,0.1,0.15,0.2) form of.Li4-xCaxTi5O12 (x=0,0.05,0.1,0.15,0.2) in the form of Ca doped LTO negative material. A simple solid state reaction method is used to synthesize.XRD results. The result shows that Ca doping does not cause the change of the lattice structure, and the high degree of impurity is obtained. The pure phase Li4-xCaxTisO12 (0 < < x < < 0.2) particle.SEM image shows that the prepared powders have similar particle appearance and the particle size distribution is between 1-2 m. In all the samples prepared, L13.9Ca0.1Ti5O12 shows higher specific capacity, better circulation and multiplying performance. After 100 cycles under 1C, 5C and 10C charge and discharge ratio, L13. The discharge capacity of 9Ca0.1Ti5O12 materials is 162.4 mA. Hg-, 148.8 mAh. G-1 and 138.7 mAh. G-1. to further improve the energy density of Li3.9Ca0.1Ti5O12 (abbreviated LCTO) electrode material, discharge the battery to the 0V cut-off voltage, LTO and LCTO through the solid-phase reaction method, indicating that the particles prepared by this method are not. The high pure phase.LCTO of any of his impurities showed higher discharge ratio and better cyclic stability than LTO. When the discharge to 0V, after 200 cycles under 1C multiplying, the capacity of LCTO was still up to 240 mAh. G-1, much higher than LTO (127.3 mAh g-1). Meanwhile, the electrochemical performance of both in the 0-2.5 V voltage range was also carried out. The effect of Ca doping on increasing the energy density of LTO was discussed at OV. Then, we selected W6+ as doping ion to improve the ratio of LTO. In air and argon atmosphere, the Li4Ti5-xWxO12 (x=0.05,0.1,0.15,0.2) form of W doped LTO sample was prepared by the sol-gel method and the following two step calcination method. It can be seen that the W doped LTO sample is slightly higher than the crystal cell parameters of the pure LTO sample. The W doped cubic spinel type structure.W doped LTO has excellent electrochemical performance as the anode material of the lithium ion battery, and the sample Li4Ti4.9W0.1O1 2 has the best multiplier and cyclic stability. When 1C, 5C and 10C charge and discharge times At the rate of 100th cycles, the discharge capacity of 162.5 mAh. G-1 and 128.1 mAh. G-1.Gd3+ as the cathode material of the lithium ion battery can significantly improve its ratio performance. However, the doping effect in the spinel LTO negative electrode has not been reported in detail yet,.Li4Ti5-XGdxO12 (x=0.05,0.10,0.15). The sample prepared by a simple solid state reaction method in the air atmosphere.XRD results showed that only a small amount of doped ions entered the lattice structure of LTO, the excess part existed in the form of Gd203 impurities, Gd doping did not change the spinel structure of LTO and the electrochemical reaction process. The size range of the prepared sample was 0.5-1.5 mu m. Compared with the undoped LTO, the multiplier performance and specific capacity of the Gd doped LTO materials are greatly improved. Especially Li4Ti4.95Gd0.05O12, it shows the best ratio and cyclic stability in all samples. However, excessive Gd203 impurities in LTO are not conducive to the exertion of its electrical properties. In addition, the low-priced Nd3+ is used. The doping of LiMn2O4 can produce oxygen ion vacancies, thus greatly improving the electronic conductivity of LiMn2O4 in the form of ionophore. Inspired by this study, we have synthesized the Nd doped LTO samples by sol-gel method, and systematically studied the structure and electrochemical properties of the prepared powders. Even at the high rate of 10C, L14Ti4.98 Nd0.02O12 still shows excellent multiplier performance and cyclic stability.Ca2+, W6+, Gd3+ and Nd3+ doped samples of four metal ions significantly improve the high rate performance of lithium ion batteries, can be used in electric batteries or wind energy, solar energy storage system devices, is conducive to environmental protection and energy conservation and emission reduction, has a very broad need. In addition, the waste lithium ion batteries used above were recovered by organic solvent method and the structure, morphology and properties of the recovered products were tested. The results showed that the final recycled LTO electrode materials showed excellent cyclic stability and reversibility and could be recycled.
【学位授予单位】：复旦大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM912
【参考文献】
相关期刊论文 前1条
1 胡国荣;张新龙;彭忠东;;锂离子电池极材料钽掺杂钛酸锂的制备及电化学性能(英文)[J];Transactions of Nonferrous Metals Society of China;2011年10期
，本文编号：2171811
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