綠色能源材料鈦酸鋰的改性及其回收再利用的研究
發(fā)布時間：2018-08-08 12:39
【摘要】：能源與環(huán)境是相互關(guān)聯(lián)的二元體系,能源消耗與環(huán)境污染并存,能源短缺制約社會發(fā)展。隨著人們對石油價格升高和日益嚴峻的環(huán)境問題的關(guān)注,發(fā)展綠色能源成為當(dāng)今能源社會的熱點。為了充分利用風(fēng)能、太陽能等清潔能源,常用鉛酸電池作為儲能電源。但鉛酸電池在回收利用過程中由于鉛泄露而造成嚴重的環(huán)境污染,給人們的健康帶來很大的危害。鋰離子電池不含有害物質(zhì),是綠色環(huán)保電源,可以應(yīng)用于電動汽車和儲能系統(tǒng),有利于節(jié)能減排及緩解二氧化碳排放所造成的溫室氣體效應(yīng)。與其他的化學(xué)電源相比,鋰離子電池具有較高的能量密度和較長的循環(huán)壽命,在可攜帶式電子設(shè)備上得到廣泛的應(yīng)用。鈦酸鋰(LTO)被認為是一種可取代傳統(tǒng)碳材料的鋰離子電池負極材料。由于LTO具有豐富的二氧化鈦原料來源、優(yōu)異的循環(huán)可逆性和穩(wěn)定性、相對較高的容量(175 mAh-g-1)及安全性能較好等優(yōu)點,它成為應(yīng)用于下一代動力鋰離子電池的重要的負極材料。LTO在充放電過程中零應(yīng)變體積及在1.55 V的高鋰插入電壓平臺,可有效地防止金屬鋰的形成,從而可以提高鋰離子電池的安全性。但是,LTO負極材料在大功率電池上的應(yīng)用受到其自身電子電導(dǎo)率差的制約。摻雜已被證明是提高其電子電導(dǎo)率的一種有效途徑,因此,在本論文中,我們通過摻雜一些金屬離子如Ca2+、W6+、Gd3+和Nd3+等提高LTO的高倍率性能。首先,我們采用Ca2+作摻雜離子來提高LTO的電導(dǎo)率。Li4-xCaxTi5O12 (x=0,0.05,0.1,0.15,0.2)形式的Ca摻雜LTO負極材料用一種簡易的固相反應(yīng)法合成。XRD結(jié)果表明,Ca摻雜沒有造成晶格結(jié)構(gòu)的改變,并且得到了沒有雜質(zhì)的高純相的Li4-xCaxTisO12 (0≤x≤0.2)顆粒。SEM圖像顯示,所制備的粉末有相似的顆粒相貌,顆粒尺寸分布在1-2 μm之間。在制備的所有樣品中,L13.9Ca0.1Ti5O12表現(xiàn)出較高的比容量、較好的循環(huán)及倍率性能。在1C、5C和10C充放電倍率下經(jīng)過100次循環(huán)后,L13.9Ca0.1Ti5O12材料的放電容量分別為162.4 mA·hg-、148.8 mAh·g-1和138.7 mAh·g-1。為了進一步提高Li3.9Ca0.1Ti5O12(簡寫為LCTO)電極材料的能量密度,將電池放電至0V截止電壓,LTO和LCTO通過固相反應(yīng)法合成。XRD結(jié)果表明,用這種方法制備的顆粒是沒有其他任何雜質(zhì)的高純相。LCTO比LTO表現(xiàn)出較高的放電比容量和較好的循環(huán)穩(wěn)定性。當(dāng)放電至0V時,在1C倍率下經(jīng)過200次循環(huán)后,LCTO的容量仍高達240 mAh·g-1,比LTO高許多(僅為127.3 mAh·g-1)。同時,對兩者在0-2.5 V電壓范圍內(nèi)的電化學(xué)性能也進行了研究,并對放電至OV時Ca摻雜對提高LTO的能量密度的影響進行了討論。接著,我們選用W6+作為摻雜離子來提高LTO的倍率性能。分別在空氣和氬氣氣氛下利用溶膠-凝膠法和之后的兩步煅燒法制備Li4Ti5-xWxO12(x=0.05,0.1,0.15,0.2)形式的W摻雜LTO樣品。可以看出,W摻雜LTO樣品比純LTO樣品的晶胞參數(shù)稍高些,W摻雜不改變LTO的立方尖晶石型結(jié)構(gòu)。W摻雜LTO作為鋰離子電池的負極材料表現(xiàn)出優(yōu)異的電化學(xué)性能,樣品Li4Ti4.9W0.1O1 2具有最好的倍率特性及循環(huán)穩(wěn)定性。當(dāng)在1C、5C和10C充放電倍率下,其第100次循環(huán)時的放電容量分別為162.5 mAh·g-1、145mAh·g-1和128.1 mAh·g-1。Gd3+作為鋰離子電池正極材料的摻雜離子可以顯著地提高其倍率性能,但是,在尖晶石型LTO負極材料中的摻雜效果至今還未作詳細報道。Li4Ti5-XGdxO12(x=0.05,0.10,0.15)樣品采用簡單的固相反應(yīng)法在空氣氣氛下制備。XRD結(jié)果表明,只有少量的摻雜離子進入了LTO的晶格結(jié)構(gòu)中,多余的部分以Gd203雜質(zhì)的形式存在,Gd摻雜不改變LTO的尖晶石型結(jié)構(gòu)及電化學(xué)反應(yīng)過程。所制備樣品的顆粒尺寸范圍為0.5-1.5μm。與未摻雜的LTO相比,Gd摻雜的LTO材料的倍率性能和比容量得到較大程度的提高。特別是Li4Ti4.95Gd0.05O12,它在所有樣品中表現(xiàn)出最好的倍率性能和循環(huán)穩(wěn)定性。但是,LTO中過多的Gd203雜質(zhì)不利于其電化學(xué)性能的發(fā)揮。另外,用低價態(tài)的Nd3+離子摻雜LiMn2O4可以產(chǎn)生氧離子空位,從而以離子載體的形式大大提高LiMn2O4的電子電導(dǎo)率。受此研究啟發(fā),我們又采用溶膠-凝膠法合成了Nd摻雜LTO樣品,并對所制備粉末的結(jié)構(gòu)和電化學(xué)性能進行了系統(tǒng)地研究。即使在10C的高倍率下,L14Ti4.98Nd0.02O12仍表現(xiàn)出優(yōu)異的倍率性能和循環(huán)穩(wěn)定性。Ca2+、W6+、Gd3+和Nd3+四種金屬離子的摻雜樣品顯著提高了鋰離子電池的高倍率性能,可用于電動車的動力電池或風(fēng)能、太陽能的儲能系統(tǒng)裝置中,有利于環(huán)境保護和節(jié)能減排,具有很廣闊的應(yīng)用前景。此外,我們利用有機溶劑法回收了上述使用過的廢舊鋰離子電池,并對回收產(chǎn)物進行了結(jié)構(gòu)、形貌和性能測試。結(jié)果表明,最終回收的LTO電極材料表現(xiàn)出優(yōu)異的循環(huán)穩(wěn)定性和可逆性,可以循環(huán)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.
【學(xué)位授予單位】：復(fù)旦大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：TM912
本文編號：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.
【學(xué)位授予單位】：復(fù)旦大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：TM912
【參考文獻】
相關(guān)期刊論文 前1條
1 胡國榮;張新龍;彭忠東;;鋰離子電池極材料鉭摻雜鈦酸鋰的制備及電化學(xué)性能(英文)[J];Transactions of Nonferrous Metals Society of China;2011年10期
，本文編號：2171811
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