本文關(guān)鍵詞： 鋰離子電池 超級電容器 過渡金屬氧化物 復(fù)合材料 協(xié)同效應(yīng)　出處：《山東大學(xué)》2017年博士論文　論文類型：學(xué)位論文

【摘要】：全球變暖和化石燃料的枯竭對人類的可持續(xù)發(fā)展造成了嚴重的威脅。為了應(yīng)對這些挑戰(zhàn),大量的研究致力于開發(fā)和利用來自于太陽能、風(fēng)能等其它可代替能源以及可再生能源的能量。考慮到這些能源的間歇性,需要可靠的能量存儲系統(tǒng)以穩(wěn)定和易控制的方式來存儲和傳遞獲得的電力。抽水蓄能、壓縮空氣儲能、飛輪儲能和電化學(xué)儲能系統(tǒng)是眾多能量存儲系統(tǒng)中關(guān)鍵和主要的成員,已引起越來越多的關(guān)注�？沙潆婋姵睾统夒娙萜魇请娀瘜W(xué)儲能系統(tǒng)的兩個重要技術(shù)子類,且已經(jīng)得到了廣泛的應(yīng)用。盡管其它類型的可充電電池,如鈉離子電池、鎂離子電池和鋁離子電池等,也在不斷發(fā)展,但其廣泛商業(yè)化受到其安全性差、持續(xù)時間不足以及可操作性等問題的嚴重妨礙,因此,當(dāng)前的可充電電池的市場仍由鋰離子電池統(tǒng)治。鋰離子電池和超級電容器工作過程都依賴于其電化學(xué)過程,但遵循不同的工作原理,因此表現(xiàn)出不同的儲能特點。鋰離子電池充放電是基于發(fā)生在塊體電極材料中的擴散控制的法拉第反應(yīng),因此過程是緩慢的。塊體儲能機制使得鋰離子電池具有高能量密度(高達180Whkg—1),但是同時具有有限的功率密度和較短的壽命(通常只有幾百個周期)。與鋰離子電池不同,超級電容器通過在電極/電解液表面的快速可逆吸附或在表面/靠近表面的快速氧化還原反應(yīng)存儲電能。因此,超級電容器有著更高的功率密度(10kWkg-1)、超長的循環(huán)壽命(105個周期)和良好的可靠性等巨大的優(yōu)勢。然而,超級電容器的能量密度比鋰離子電池低得多,商業(yè)化的超級電容器通常小于10Whkg-1。因此迫切需要改善當(dāng)前鋰離子電池和超級電容器的儲電性能來滿足未來電子設(shè)備日益嚴格的要求。過渡金屬氧化物被認為是最有潛力的用于鋰離子電池和超級電容器的電極材料,因為其具有成本低、易于合成和環(huán)境友好等優(yōu)點,然而單一組分的過渡金屬氧化物過快的比容量(電容)衰減、差的導(dǎo)電性、明顯的體積膨脹和大的電壓滯后,使得它們的商業(yè)化嚴重受挫。制備具有兩種或多種組分,形貌易控制的過渡金屬氧化物的復(fù)合材料對提高鋰離子電池和超級電容器的儲電性能具有非常重要的意義。本論文通過采用不同的策略成功地設(shè)計和制備了具有微納米尺寸、大的比表面積、良好導(dǎo)電性和結(jié)構(gòu)穩(wěn)定性以及快速的離子和電子傳輸?shù)膹?fù)合材料。復(fù)合材料的特殊結(jié)構(gòu)使其具有比單一組分優(yōu)異的電化學(xué)性能,如高的比容量(電容),長的循環(huán)壽命和高倍率性能,這主要歸因于多種組分的協(xié)同作用。本論文的研究工作如下。(1)通過結(jié)合溶劑熱和溶膠-凝膠法成功構(gòu)建了三維多孔的Co3O4@a-TiO2核殼微/納米結(jié)構(gòu),值得一提的是,通過在溶膠-凝膠過程中精確調(diào)節(jié)乙醇和水的體積比可獲得具有可控孔徑的殼層a-TiO2。這是首次使用核殼Co3O4@a-TiO2微/納米結(jié)構(gòu)作為鋰離子電池的負極材料。該復(fù)合結(jié)構(gòu)的電化學(xué)性能與其結(jié)構(gòu)息息相關(guān)。這種新穎的復(fù)合結(jié)構(gòu)作為先進的鋰離子電池負極材料時表現(xiàn)出高的比容量,長的循環(huán)壽命和良好的倍率性能,主要歸因于殼層a-TiO2優(yōu)異的穩(wěn)定性,核層Co3O4的高比容量和復(fù)合材料優(yōu)化的孔徑分布。在0.5 Ag-1的電流密度下獲得800 mAhg-1的高可逆比容量,在60次充放電循環(huán)后依然保持該比容量穩(wěn)定。(2)過渡金屬氧化物分級結(jié)構(gòu)的制備已經(jīng)得到深入研究,但是合成多組分分級結(jié)構(gòu)的過渡金屬氧化物仍然存在巨大挑戰(zhàn)。本文中報道了一種通用的方法來制備三組分過渡金屬氧化物,即MnO2@NiO/NiMoO4納米線@納米片分級多孔復(fù)合結(jié)構(gòu)(MnO2@NiO/NiMoO4HPCSs)。通過化學(xué)溶液法以及隨后的煅燒處理,MnOOH@NiMo前驅(qū)體拓撲轉(zhuǎn)化為MnO2@NiO/NiMoO4 HPCSs,并沒有發(fā)生顯著地結(jié)構(gòu)變化,超薄的NiO/NiMoO4納米片互連成蜂窩狀結(jié)構(gòu)并且具有豐富的間隙孔。對比實驗結(jié)果表明六次甲基四胺和溶液體系在MnOOH@NiMo前驅(qū)體的形成過程中起到重要作用。當(dāng)用作超級電容器電極材料時,單位面積負載量高達5 mg cm2 的 MnO2@NiO/NiMoO4HPCSs 在 1 Ag-1 的電流密度下提供 918 F g-1 的比電容,并且保持良好的循環(huán)穩(wěn)定性,其顯示出比單一組分組成的電極材料更好的電化學(xué)性能�；贛nO2@NiO/NiMoO4HPCSs(正極)和活性炭(負極)的高電壓非對稱超級電容器表現(xiàn)出優(yōu)異的循環(huán)穩(wěn)定性,高的能量密度(26.5 Wh kg-1)和功率密度(401 Wkg-1)。證實了該多組分分級結(jié)構(gòu)作為先進的超級電容器電極材料的優(yōu)越性。(3)金屬有機簇是零維的、獨立的、離散的分子,其具有多于一個的金屬中心,是通過橋連陰離子和外殼有機配體聚集成的一個整體。到目前為止,還沒有以金屬有機簇為前驅(qū)體來制備微/納米復(fù)合結(jié)構(gòu)的報道,并且其獨特的結(jié)構(gòu)帶來的優(yōu)異性能也未被發(fā)現(xiàn)的。本文中,通過在氬氣氛圍中500 ℃下熱解混合價的八核Mn簇得到了一種特殊的復(fù)合結(jié)構(gòu),MnO@Mn3O4核殼納米顆粒嵌入在氮摻雜的多孔碳骨架內(nèi),即MnO@Mn3O4/NPCFs,并將其應(yīng)用于鋰離子電池。由于其新穎的結(jié)構(gòu)和組成特點,這些獨特的MnO@Mn3O4/NPCFs表現(xiàn)出優(yōu)異的電化學(xué)性能:超高的比容量,超長的循環(huán)穩(wěn)定性和優(yōu)異的倍率性能,同時解決了電極材料在充放電過程中的粉化、慢的離子/電子動力學(xué)、顆粒團聚等問題。這為設(shè)計和構(gòu)造下一代的鋰離子電池負極材料開辟了新的途徑。(4)通過簡易的兩步法成功制備了高比容量的MoO2/石墨烯復(fù)合材料,即MoO2納米顆粒均勻地分散在rGO納米片上。在MoO2NP/rGO二維納米復(fù)合結(jié)構(gòu)中,rGO可以作為負載具有電化學(xué)活性的MoO2納米顆粒的有利支撐,同時,Mo02納米顆粒的存在有效地防止了 rGO的堆疊,兩者的有利結(jié)合為儲鋰提供了更多的電化學(xué)活性位點。MoO2NP/rGO納米復(fù)合材料作為鋰離子電池負極材料時表現(xiàn)出優(yōu)異的循環(huán)和倍率性能:在0.2 Ag-1的電流密度下循環(huán)150圈比容量能夠維持在1516.4 mAh g-1,即使在較高的電流密度1.0 Ag-1充放電300個循環(huán)后,比容量仍穩(wěn)定在641 mAh g-1。該合成方法可擴展到制備其它過渡金屬氧化物/石墨烯基復(fù)合材料進而提高其在鋰離子電池中的電化學(xué)性能。
[Abstract]:A serious threat to global warming and depletion of fossil fuels for human sustainable development. In order to deal with these challenges, a lot of research dedicated to the development and utilization of wind energy from solar energy, and other alternative energy sources of energy and renewable energy. Considering these energy needs intermittent, energy storage system in a stable and reliable easy to control the way to store and transfer the power. Pumped storage, compressed air energy storage flywheel energy storage and electrochemical energy storage system is the main and key members of the energy storage system, has attracted more and more attention. The rechargeable battery and super capacitor is an electrochemical energy storage system of two important technology sub class, and has been widely used. Although other types of rechargeable batteries, such as sodium ion, magnesium ion battery and aluminum ion batteries, but also in the continuous development, But the widespread commercialization by its poor security, seriously hamper, duration of insufficient and the operability of the rechargeable battery, the current market is still a lithium ion battery rule. Lithium ion batteries and super capacitors are dependent on the working process of the electrochemical process, but follow the different principle, so the performance of different storage characteristics of lithium ion battery charging and discharging is the Faraday reaction diffusion occurs in the bulk of the electrode materials based on control, so the process is slow. Bulk storage mechanism makes lithium ion battery with high energy density (up to 1 180Whkg), but also has the power density and the Co. short life (usually only a few hundred cycles). Unlike lithium ion battery, super capacitor through the electrode / electrolyte surface rapid reversible adsorption or in rapid oxidation of the surface / near surface reaction To store electrical energy. Therefore, the super capacitor has a higher power density (10kWkg-1), long cycle life (105 cycles) and good reliability of huge advantage. However, the super capacitor energy density is much lower than lithium ion batteries, electric energy storage performance of the super capacitor is usually commercial less than 10Whkg-1. so there is an urgent need to improve the current lithium ion battery and super capacitor to meet the increasingly stringent requirements of electronic equipment in the future. The transition metal oxides are considered to be the most promising electrode materials for lithium ion batteries and super capacitors, because of its low cost, easy synthesis and environmental friendly, however, transition metal oxide single component of the excessive capacity (capacitance) attenuation, low conductivity, voltage apparent volume expansion and large lag, making them the business suffered a serious setback. The preparation of two or more Components, has a very important significance to the charge storage properties of transition metal oxide composite material to improve the morphology control of lithium ion batteries and super capacitors. This paper adopts different strategies successfully designed and prepared with micro or nano size, large surface area, good conductivity and structure stability and the composite ion and fast electron transport. The special structure of composite material which has excellent electrochemical performance than single component, such as high specific capacity (capacitance), long cycle life and high rate performance, which is mainly due to the various components of synergy. The research work of this thesis is as follows. (1) by combining solvothermal and sol-gel method to construct Co3O4@a-TiO2 core-shell porous micro / nano structure, it is worth mentioning that, by precisely adjusting the ethanol and water in the sol gel process volume The ratio of pore size controllable shell obtained a-TiO2. this is the first use of nuclear shell Co3O4@a-TiO2 micro / nano structure as anode materials for lithium ion batteries. The electrochemical performance of the composite structure is closely related to its structure. The composite structure of this novel as the advanced lithium ion battery negative electrode materials exhibit high specific capacity, long cycling life and the good rate performance, mainly due to the excellent stability of a-TiO2 shell, high capacity Co3O4 core and aperture optimization of composite material distribution. To obtain a high reversible 800 mAhg-1 at the current density of 0.5 Ag-1 capacity, after 60 cycles the specific capacity remained stable. (2) transition metal oxides the hierarchical structure of the preparation has been studied deeply, but the synthesis of transition metal oxide multicomponent hierarchical structure is still a huge challenge. This paper reports a general The method of preparation of three component transition metal oxide, MnO2@NiO/NiMoO4 nanowires @ nano hierarchical porous composite structure (MnO2@NiO/NiMoO4HPCSs). The chemical solution method and subsequent calcination of the precursor of MnOOH@NiMo topology into MnO2@NiO/NiMoO4 HPCSs, there is no structural changes significantly, the ultrathin NiO/NiMoO4 nanosheets interconnect into honeycomb structure and having a clearance hole rich. The experimental results show that the six methyl four amine solution system and plays an important role in the formation process of MnOOH@NiMo precursor. When used as electrode material for super capacitor, unit area load up to 5 mg cm2 MnO2@NiO/NiMoO4HPCSs at the current density of 1 Ag-1 918 F g-1 the specific capacitance, and maintain a good cycle stability, which shows that the electrochemical performance of electrode material is better than the single component of the base. In MnO2@NiO/NiMoO4HPCSs (positive) and activated carbon (negative) high voltage asymmetric supercapacitor exhibits excellent cycling stability, high energy density (26.5 Wh kg-1) and power density (401 Wkg-1). Proved that the multi-component hierarchical structure as an advanced supercapacitor electrode material (superiority. 3) metal organic clusters is zero dimensional, independent, discrete molecules, which has more than one metal center, through bridging anions and organic ligand shell poly a whole integration. So far, not with metal organic clusters as precursor for the preparation of reports of micro / nano composite structure the excellent properties and its unique structure also has not been found. In this paper, by obtaining a compound with special structure of eight nuclear Mn cluster under 500 DEG C for pyrolysis of mixed valence in argon atmosphere, MnO@Mn3O4 core-shell nanoparticles embedded in nitrogen doped The porous carbon skeleton, namely MnO@Mn3O4/NPCFs, and its application in lithium ion battery. Because of its novel structure and composition characteristics, these unique MnO@Mn3O4/NPCFs exhibited excellent electrochemical properties: high specific capacity, long cycling stability and excellent rate can also solve the powder electrode material in charge during the process of discharge, slow ion / electron dynamics, particle aggregation and other issues. It opens up a new way for lithium ion battery anode materials for the design and construction of the next generation. (4) by a simple two step method to fabricate MoO2/ graphene composite materials with high capacity, namely MoO2 nanoparticles uniformly dispersed in rGO nanosheets. In 2D MoO2NP/rGO nano composite structure, rGO can be used as a powerful support, MoO2 nanoparticles loaded with electrochemical activity at the same time, Mo02 nanoparticles are effectively prevented rGO The stack, both favorable combination of lithium storage provides electrochemical active sites of.MoO2NP/rGO nano composite materials more as anode materials for lithium ion batteries exhibit excellent cycle and rate performance: 150 cycles at the current density of 0.2 Ag-1 capacity can maintain at 1516.4 mAh g-1, even at higher current density of 1 Ag-1 300 charge discharge cycles, the capacity ratio remained stable at 641 mAh g-1. this method can be extended to prepare other transition metal oxides / graphene composites and improve its electrochemical performance.

【學(xué)位授予單位】：山東大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：TB33;TM53;TM912

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本文編號：1444736