本文關(guān)鍵詞：氧化鐵復(fù)合納米材料的水熱制備及其超級電容特性研究　出處：《太原理工大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 超級電容器 氧化鐵 復(fù)合納米材料 碳納米管 石墨烯

【摘要】：超級電容器作為一種新型的儲能器件,由于具有低等效串聯(lián)電阻,快速功率輸出,高能量密度,大功率密度,高循環(huán)效率,長循環(huán)壽命等優(yōu)異性能,目前,已成為國內(nèi)外清潔能源領(lǐng)域的研究熱點之一。氧化鐵,作為一種典型的過渡金屬氧化物半導(dǎo)體材料,其具有良好的贗電容特性。同時,與傳統(tǒng)超級電容器材料(如,石墨烯、碳納米管等碳基材料、氧化釕、氧化鈷、氧化鎳、氧化錳等過渡金屬氧化物材料)相比,氧化鐵納米材料具有含量豐富、制備成本低、環(huán)境友好等眾多優(yōu)點。然而,單純的氧化鐵納米材料導(dǎo)電性能較低,循環(huán)性能較差,比容量不高。針對上述問題,本論文通過水熱法合成了不同形貌的氧化鐵納米顆粒,并將不同形貌的氧化鐵納米顆粒與石墨烯和碳納米管進(jìn)行復(fù)合,并系統(tǒng)研究了氧化鐵/碳納米管、氧化鐵/石墨烯等氧化鐵基復(fù)合納米材料的超級電容特性。論文詳細(xì)內(nèi)容如下:(1)利用水熱法合成出不同形貌的氧化鐵納米材料,并對材料的形貌和電化學(xué)性能進(jìn)行表征。初步探討了[H_2PO_4]~-對材料形貌的影響。實驗表明磷酸二氫根離子附著在納米晶體的側(cè)壁,導(dǎo)致晶體沿[006]軸向生長。合成出的不同長徑比的棒狀納米顆粒,有效增大了材料的比表面積,擴(kuò)大了電解液離子與電極活性物質(zhì)的接觸面積,提高了電子和質(zhì)子在電極材料中的傳遞速率,由此造成材料的電化學(xué)性能產(chǎn)生顯著差異。結(jié)果表明長徑比最小的顆粒表現(xiàn)出最優(yōu)的比容量和穩(wěn)定性。(2)利用水熱法制備了多種形貌的氧化鐵/多壁碳納米管復(fù)合材料,對Fe_2O_3/MWCNT復(fù)合材料進(jìn)行了結(jié)構(gòu)表征和電化學(xué)性能測試。結(jié)果表明粒徑較小的Fe_2O_3納米顆粒能夠生長在碳納米管的管壁上,而粒徑較大的Fe_2O_3納米顆粒卻無法在管壁上生長。粒徑為5 nm、30 nm、環(huán)狀、鏤空環(huán)狀、片狀的氧化鐵與碳納米管復(fù)合后兼顧了碳納米管和氧化鐵的優(yōu)點,同時又增加了材料的比表面積,加快了電子在電極材料中的傳遞速率,因此提高了Fe_2O_3/MWCNTs的電容性能。在電流密度為1A/g時,鏤空環(huán)狀氧化鐵/多壁碳納米管復(fù)合材料的比電容最高達(dá)到183 F/g并且循環(huán)性能得到明顯提升,表明氧化鐵/多壁碳納米管復(fù)合材料具有良好的超級電容性能。(3)利用水熱法制備了多種形貌的氧化鐵/石墨烯復(fù)合納米材料,并對Fe_2O_3/r GO復(fù)合納米材料進(jìn)行形貌表征和電化學(xué)性能測試,可以看到Fe_2O_3負(fù)載在石墨烯的層狀結(jié)構(gòu)上,形成二維結(jié)構(gòu),這種結(jié)構(gòu)不僅縮短了離子的遷移距離,而且提高了活性材料的利用率;同時,負(fù)載有粒徑為5 nm、30 nm、環(huán)狀、鏤空環(huán)狀、片狀的Fe_2O_3的石墨烯提高了材料的導(dǎo)電性,加快了有效離子和電荷的傳輸速率,從而提高了復(fù)合材料的電容性能。在電流密度為1A/g時,粒徑為30 nm的Fe_2O_3/r GO比容量為135 F/g并且在經(jīng)過循環(huán)充放電1000圈后其比容量保留率最高為80%,表明氧化鐵/石墨烯復(fù)合材料相較純的氧化鐵和氧化鐵/多壁碳納米管復(fù)合材料,具有更好的超級電容性能。
[Abstract]:Supercapacitor is a new energy storage device, due to its low equivalent series resistance, fast power output, high energy density, high power density, high cycle efficiency, long cycle life and excellent performance, at present, has become a hot research topic in the field of clean energy field. Iron oxide, as a typical transition the metal oxide semiconductor material, which has good pseudocapacitive properties. At the same time, with the traditional super capacitor materials (e.g., graphene, carbon nanotubes and other carbon based material, ruthenium oxide, cobalt oxide, nickel oxide, manganese oxide and transition metal oxide materials), iron oxide nanomaterials have abundant preparation cost low, many advantages of environmental friendly. However, the conductive properties of pure iron oxide nano materials is low, poor cycle performance, high specific capacity. According to the above problems, this paper through the hydrothermal method with different morphologies were synthesized. Iron oxide nanoparticles, and different morphologies of composite iron oxide nanoparticles and graphene and carbon nanotubes, and the system of iron oxide / carbon nanotubes, super capacitor characteristics of iron oxide / graphene oxide composite nano materials. The detailed contents are as follows: (1) the synthesis of iron oxide nanomaterials with different morphologies by hydrothermal method and morphology and electrochemical performance of the materials were characterized. Preliminary study on the effect of [H_2PO_4]~- on the morphology of the materials. The results show that two hydrogen phosphate ions attached to the nano crystal wall, lead crystal along [006] axial growth. Different length diameter ratio of the synthesis of rod like nano particles, can increase the ratio of material the surface area, expand the contact area of the electrolyte and electrode active material, electron transfer rate and proton in the electrode material is improved, the resulting material electrochemical performance Have a significant difference. The results show that the ratio of length to diameter of the smallest particles exhibit optimal capacity and stability. (2) a variety of morphologies of iron oxide / multiwalled carbon nanotube composites were prepared by hydrothermal method on Fe_2O_3/MWCNT composites were characterized and electrochemical performance test. The results show that the smaller particle size of Fe_2O_3 nanoparticles the particles can grow in carbon nanotube walls, while the larger particle size of Fe_2O_3 nanoparticles is not on the pipe wall growth. The particle size is 5 nm, 30 nm, ring, ring hollow, flaky iron oxide and carbon nanotube composite after the advantages of carbon nanotubes and iron oxide, while the increase of material the specific surface area, accelerate the electron transfer rate in the electrode material, thereby improving the performance of Fe_2O_3/MWCNTs capacitor. When the current density is 1A/g, the hollow annular iron oxide / multiwalled carbon nanotubes composite materials than electricity The highest volume reached 183 F/g and the cycle performance has improved significantly, showed that iron oxide / multiwalled carbon nanotube composite material with super capacitor with good performance. (3) a variety of morphologies of iron oxide / graphene nanocomposites were prepared by hydrothermal method, and the Fe_2O_3/r GO composite nano materials morphology characterization and electrochemical performance testing. You can see the Fe_2O_3 load in the layered structure of graphene, a two-dimensional structure is formed, the structure not only reduces the migration distance of ions, but also improve the utilization of the active material; at the same time, loaded with the diameter of 5 nm and 30 nm, ring, ring hollow, graphene sheet Fe_2O_3 improved conductive material to speed up the transmission rate, effective ion and charge, thereby improving the capacitance properties of the composites. When the current density is 1A/g, the size of 30 nm Fe_2O_3/r GO capacity is 135 F/g and the After 1000 cycles of charge and discharge, the specific capacity retention rate is 80%, indicating that iron oxide / graphene composite material has better supercapacitor performance than pure iron oxide and iron oxide / multi walled carbon nanotube composite.

【學(xué)位授予單位】：太原理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TM53;TB383.1

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本文編號：1429386