金屬氧化物多級結(jié)構(gòu)的制備及其在超級電容器中的應(yīng)用
發(fā)布時間：2018-12-14 10:50
【摘要】：隨著對能源需求的增長和環(huán)境保護意識的增強,可持續(xù)發(fā)展的新能源及其相關(guān)的能源儲存技術(shù)受到越來越多的關(guān)注。超級電容器被認為是一種十分具有潛力的儲能器件,因為它具有高的功率密度,長的循環(huán)壽命以及快速的充放電性能。近年來,超級電容器的研究熱點主要集中在制備容量高和循環(huán)性能好的電極材料上。其中金屬氧化物電極材料因其具有較高的理論容量而備受關(guān)注,但是導電性差及循環(huán)壽命短的缺陷仍是制約金屬氧化物材料發(fā)展的一大障礙。本文通過優(yōu)化電極材料的納米結(jié)構(gòu)成功制備了幾種結(jié)構(gòu)不同的鎳鈷基金屬氧化物電極材料,并系統(tǒng)的討論了形貌與結(jié)構(gòu)對電極材料電化學性能的影響。實驗工作及成果如下:1.通過簡單的水熱法在泡沫鎳上成功合成了核殼結(jié)構(gòu)NiCo_2O_4@NiMoO_4的納米片陣列。在最優(yōu)的制備條件下,多級結(jié)構(gòu)NiCo_2O_4@NiMoO_4電極的電化學活性要遠遠高于NiCo_2O_4單一組分電極。在電流密度為5mA cm-2時,復(fù)合電極的面積比容量和質(zhì)量比容量分別為6.91 F·cm-2和1974 F·g-1,其在40 m A·cm-2的電流密度下循環(huán)5000次后的容量保持率為76%。此外,我們以活性炭為負極,最優(yōu)條件下制備的核殼結(jié)構(gòu)NiCo_2O_4@NiMoO_4的納米片電極材料為正極,組裝了非對稱超級電容器,該電容器具有較高的能量密度和優(yōu)異的循環(huán)性能。2.以相似的方法合成了NiCo_2O_4@CoMoO_4的納米片陣列。由于納米結(jié)構(gòu)對活性材料獨特的保護機制,復(fù)合電極展現(xiàn)了極為優(yōu)異的電化學性能,高的面積比容量(在5 mA·cm-2電流密度下5.4 F·cm-2)、好的容量保持率及優(yōu)秀的循環(huán)穩(wěn)定性。由最優(yōu)條件的電極與AC/grapheme復(fù)合材料組裝的非對稱超級電容器在593.5 W·kg-1的功率密度下?lián)碛袠O高的能量密度42.75 Wh·kg-1。此外,該非對稱電容器在10000個循環(huán)后容量幾乎無衰減。3.通過水熱法制備了鎳鋁雙氫氧化物納米片(Ni-Al LDH)陣列,然后以其為一層結(jié)構(gòu)合成Ni-Al LDH@CoMoO_4納米陣列電極,并討論了水熱時間對電極材料電化學性能的影響。
[Abstract]:With the increase of energy demand and the increasing awareness of environmental protection, more and more attention has been paid to the sustainable development of new energy sources and their related energy storage technologies. Supercapacitors are considered to be potential energy storage devices because of their high power density, long cycle life and fast charge-discharge performance. In recent years, the research focus of supercapacitors is mainly on the preparation of electrode materials with high capacity and good cycling performance. Among them, metal oxide electrode materials have attracted much attention because of their high theoretical capacity. However, the defects of poor conductivity and short cycle life are still a major obstacle to the development of metal oxide materials. In this paper, several kinds of nickel-cobalt based metal oxide electrode materials with different structures have been successfully prepared by optimizing the nanostructures of electrode materials, and the effects of morphology and structure on the electrochemical properties of electrode materials have been systematically discussed. The experimental work and results are as follows: 1. The core-shell NiCo_2O_4@NiMoO_4 nanoarrays were successfully synthesized on nickel foam by a simple hydrothermal method. Under the optimal preparation conditions, the electrochemical activity of multistage NiCo_2O_4@NiMoO_4 electrode is much higher than that of NiCo_2O_4 single component electrode. When the current density is 5mA cm-2, the area specific capacity and mass specific capacity of the composite electrode are 6.91 F cm-2 and 1974 F g-1, respectively. The capacity retention rate of the composite electrode after 5000 cycles at the current density of 40 Ma cm-2 is 76. In addition, we fabricated asymmetric supercapacitors using activated carbon as negative electrode and nanocrystalline electrode material of core-shell structure NiCo_2O_4@NiMoO_4 as positive electrode under optimal conditions. The capacitor has high energy density and excellent cycle performance. 2. NiCo_2O_4@CoMoO_4 nanochip arrays were synthesized in a similar way. Because of the unique protective mechanism of nanostructures on the active materials, the composite electrodes exhibit excellent electrochemical performance and high area specific capacity (5.4 F cm-2 at 5 mA cm-2 current density). Good capacity retention and excellent cycle stability. An asymmetric supercapacitor composed of an optimal electrode and AC/grapheme composite has an extremely high energy density of 42.75 Wh kg-1. at a power density of 593.5 W kg-1. In addition, the capacity of the asymmetric capacitor almost has no attenuation after 10,000 cycles. The nickel-aluminum dihydroxide (Ni-Al LDH) nanocrystalline arrays were prepared by hydrothermal method, and then the Ni-Al LDH@CoMoO_4 nanoscale array electrodes were synthesized by using them as a layer structure. The effect of hydrothermal time on the electrochemical properties of the electrode materials was discussed.
【學位授予單位】：電子科技大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TM53;TB383.1
本文編號：2378483
[Abstract]:With the increase of energy demand and the increasing awareness of environmental protection, more and more attention has been paid to the sustainable development of new energy sources and their related energy storage technologies. Supercapacitors are considered to be potential energy storage devices because of their high power density, long cycle life and fast charge-discharge performance. In recent years, the research focus of supercapacitors is mainly on the preparation of electrode materials with high capacity and good cycling performance. Among them, metal oxide electrode materials have attracted much attention because of their high theoretical capacity. However, the defects of poor conductivity and short cycle life are still a major obstacle to the development of metal oxide materials. In this paper, several kinds of nickel-cobalt based metal oxide electrode materials with different structures have been successfully prepared by optimizing the nanostructures of electrode materials, and the effects of morphology and structure on the electrochemical properties of electrode materials have been systematically discussed. The experimental work and results are as follows: 1. The core-shell NiCo_2O_4@NiMoO_4 nanoarrays were successfully synthesized on nickel foam by a simple hydrothermal method. Under the optimal preparation conditions, the electrochemical activity of multistage NiCo_2O_4@NiMoO_4 electrode is much higher than that of NiCo_2O_4 single component electrode. When the current density is 5mA cm-2, the area specific capacity and mass specific capacity of the composite electrode are 6.91 F cm-2 and 1974 F g-1, respectively. The capacity retention rate of the composite electrode after 5000 cycles at the current density of 40 Ma cm-2 is 76. In addition, we fabricated asymmetric supercapacitors using activated carbon as negative electrode and nanocrystalline electrode material of core-shell structure NiCo_2O_4@NiMoO_4 as positive electrode under optimal conditions. The capacitor has high energy density and excellent cycle performance. 2. NiCo_2O_4@CoMoO_4 nanochip arrays were synthesized in a similar way. Because of the unique protective mechanism of nanostructures on the active materials, the composite electrodes exhibit excellent electrochemical performance and high area specific capacity (5.4 F cm-2 at 5 mA cm-2 current density). Good capacity retention and excellent cycle stability. An asymmetric supercapacitor composed of an optimal electrode and AC/grapheme composite has an extremely high energy density of 42.75 Wh kg-1. at a power density of 593.5 W kg-1. In addition, the capacity of the asymmetric capacitor almost has no attenuation after 10,000 cycles. The nickel-aluminum dihydroxide (Ni-Al LDH) nanocrystalline arrays were prepared by hydrothermal method, and then the Ni-Al LDH@CoMoO_4 nanoscale array electrodes were synthesized by using them as a layer structure. The effect of hydrothermal time on the electrochemical properties of the electrode materials was discussed.
【學位授予單位】：電子科技大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TM53;TB383.1
【參考文獻】
相關(guān)期刊論文 前1條
1 余麗麗;朱俊杰;趙景泰;;超級電容器的現(xiàn)狀及發(fā)展趨勢[J];自然雜志;2015年03期
，本文編號：2378483
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