發(fā)布時(shí)間：2018-04-29 00:29

  本文選題：超級(jí)電容器 + 氮摻雜多孔炭�。� 參考：《安徽大學(xué)》2017年碩士論文

【摘要】：超級(jí)電容器,作為一種新型的電能存儲(chǔ)器件,具有高功率密度、優(yōu)異的穩(wěn)定性、快速充放電功能以及環(huán)境友好等諸多優(yōu)點(diǎn),在電子、通信、交通、電力、工業(yè)節(jié)能、國防等許多領(lǐng)域具有重要的應(yīng)用價(jià)值和巨大的市場潛力。電極材料是超級(jí)電容器的關(guān)鍵組成部分,常見的超級(jí)電容器電極材料包括碳材料、過渡金屬氧化物和導(dǎo)電聚合物等。碳材料主要呈現(xiàn)雙電層電容特性,具有優(yōu)異的充放電循環(huán)穩(wěn)定性,符合實(shí)際應(yīng)用中對(duì)器件壽命的高要求,但是比電容相對(duì)較低。過渡金屬氧化物和導(dǎo)電聚合物主要呈現(xiàn)贗電容特性,依賴可逆的化學(xué)吸附/脫附或氧化還原反應(yīng)來儲(chǔ)存電荷,雖然具有較高的比電容,但是電容循環(huán)穩(wěn)定性較差。這些電極材料既有各自的優(yōu)勢(shì),又有其不足。因此,對(duì)電極材料的研究并非僅限于單一組分材料,復(fù)合材料往往可以呈現(xiàn)出更加出色的電化學(xué)性能。碳基復(fù)合電極材料因其原料豐富、價(jià)格低廉、制備工藝簡單且性能優(yōu)異而倍受關(guān)注。本論文對(duì)碳基復(fù)合電極材料的制備、電化學(xué)性能及其在超級(jí)電容器中的應(yīng)用進(jìn)行了研究,主要研究內(nèi)容如下:一、氮摻雜多孔炭的制備及其電容性能研究以天然產(chǎn)物為碳源,三聚氰胺為氮源,經(jīng)碳化和氫氧化鉀(KOH)高溫活化后得到氮摻雜多孔炭(NPC)。在800℃下活化所得的NPC-800呈現(xiàn)多孔狀的微觀形貌,氮元素含量達(dá)到6.45 wt%,主要以吡啶氮和吡咯氮的形式存在。將NPC作為活性材料制備成電極并組裝成對(duì)稱型超級(jí)電容器。在兩電極體系下,以6 mol L-1 KOH為電解液,通過恒電流充放電(GCD)和循環(huán)伏安(CV)測試表明:電流密度為0.1 Ag-1時(shí),NPC-800所組裝的超級(jí)電容器的比電容值達(dá)到145 F g-1,而且當(dāng)功率密度為50 W kg-1時(shí),能量密度可達(dá)到20 Wh kg-1。經(jīng)過1000次循環(huán)充放電后,其比電容仍然能保持96.9%,庫侖效率穩(wěn)定在99%,以上結(jié)果表明NPC具有優(yōu)良的電容特性和循環(huán)穩(wěn)定性,適用于超級(jí)電容器電極材料。二、氧化石墨烯/聚吡咯二元復(fù)合材料的合成及其電容性能研究采用改進(jìn)的Hummers法制得氧化石墨烯(GO),再采用原位聚合法合成氧化石墨烯/聚吡咯(GO/PPy)二元復(fù)合材料。掃描電子顯微鏡(SEM)表征可知該二元復(fù)合材料呈現(xiàn)褶皺的納米片層形貌,這是由于PPy通過π-π堆疊、氫鍵和靜電等相互作用從而在GO表面形成一層致密的覆蓋層。在三電極系統(tǒng)中進(jìn)行GCD和CV測試,結(jié)果表明在0.5Ag-1的電流密度下,GO/PPy的比電容值達(dá)到468Fg-1,高于單一 PPy電極的比電容值(267Fg-1)。而且,由于GO與PPy之間的協(xié)同效應(yīng),GO/PPy的倍率性能和循環(huán)穩(wěn)定性也都得到了顯著的提升。由此可見,PPy與GO復(fù)合以后所得GO/PPy二元復(fù)合物的電容性能得到了增強(qiáng)。三、氧化石墨烯/碳量子點(diǎn)/聚吡咯三元復(fù)合材料的合成及其電容性能研究分別采用微波輔助熱解法、水熱法以及原位聚合法合成了碳量子點(diǎn)(CDs)、氧化石墨烯/碳量子點(diǎn)(GO/CDs)二元復(fù)合物和氧化石墨烯/碳量子點(diǎn)/聚吡咯(GO/CDs/PPy)三元復(fù)合物。通過在GO納米片與PPy層之間引入CDs可以提升三元復(fù)合材料的電子傳輸并降低電極的內(nèi)部電阻以及電荷傳輸電阻。此外,具有高比表面積的CDs可以增強(qiáng)GO、CDs以及PPy三者之間的界面性能從而增大三元復(fù)合材料的介電常數(shù)。在0.5 A g-1的電流密度下,GO/CDs/PPy呈現(xiàn)出576 Fg-1的比電容,將其組裝成對(duì)稱型超級(jí)電容器,在250Wkg-1的功率密度下可獲得的最大能量密度為30.1 Wh kg-1。更重要的是,三元復(fù)合物經(jīng)過5000次充放電后仍具有較高的比電容,表現(xiàn)出優(yōu)異的循環(huán)穩(wěn)定性。為了評(píng)價(jià)電極材料的實(shí)際應(yīng)用價(jià)值,我們將5個(gè)超級(jí)電容器串聯(lián)成一個(gè)簡易模組,發(fā)現(xiàn)僅需充電17秒就可以將59個(gè)發(fā)光二極管點(diǎn)亮超過1分鐘。上述結(jié)果表明,CDs在提升GO/CDs/PPy三元復(fù)合材料的電容性能過程中起到了重要的作用,所構(gòu)筑的雙電層電容/贗電容混合超級(jí)電容器具有高的能量密度和優(yōu)異的循環(huán)穩(wěn)定性,從而具有潛在的市場應(yīng)用前景。
[Abstract]:Supercapacitor, as a new type of electric energy storage device, has many advantages, such as high power density, excellent stability, fast charging and discharging function and environment friendly. It has important value and great market potential in many fields, such as electronic, communication, traffic, electric power, industrial energy saving, national defense and many other fields. Electrode material is a supercapacitor. The common supercapacitor electrode materials include carbon materials, transition metal oxides and conductive polymers. Carbon materials mainly exhibit double layer capacitance characteristics, and have excellent charge discharge cycle stability. It is in line with the high requirement for the life of the device in practical applications, but the specific capacitance is relatively low. And the conductive polymer mainly presents pseudo capacitance, depends on reversible chemical adsorption / desorption or redox reaction to store charge. Although it has a higher specific capacitance, the stability of the capacitance cycle is poor. These electrode materials have their own advantages and disadvantages. Therefore, the study of electrode materials is not limited to single component. Composite materials often show excellent electrochemical properties. Carbon based composite electrode materials have attracted much attention because of their rich raw materials, low price, simple preparation and excellent performance. This paper has studied the preparation, electrochemical properties and applications of carbon based composite electrode materials in super capacitor. The contents are as follows: 1. Study on the preparation and capacitive performance of nitrogen doped porous carbon with natural products as carbon source, melamine as nitrogen source, nitrogen doped porous carbon (NPC) after carbonization and potassium hydroxide (KOH) activation at high temperature. The activation of NPC-800 at 800 centigrade shows a multi pore morphology, and the content of nitrogen element reaches 6.45 wt%, mainly with pyridine. In the form of nitrogen and pyrrole nitrogen, the NPC was prepared as the active material and assembled into a symmetrical supercapacitor. Under the two electrode system, 6 mol L-1 KOH was used as the electrolyte, and the constant current charge discharge (GCD) and cyclic voltammetry (CV) test showed that the specific capacitance of the supercapacitor assembled by NPC-800 was reached when the current density was 0.1 Ag-1. To 145 F g-1, and when the power density is 50 W kg-1, the energy density can reach 20 Wh kg-1. after 1000 cycles charge and discharge, the specific capacitance remains 96.9% and the coulomb efficiency is stable at 99%. The above results show that NPC has excellent capacitance and cyclic stability. It is suitable for super capacitor electrode material. Two, graphene oxide / poly (graphite oxide). Synthesis and capacitive properties of pyrrole two element composite materials, graphene oxide (GO) was obtained by improved Hummers method, and two element composites of graphene oxide / polypyrrole (GO/PPy) were synthesized by in-situ polymerization. The scanning electron microscope (SEM) was used to characterize the nanoscale lamellar morphology of the two element composite material, which was due to PPy By pion pion stacking, hydrogen bonding and electrostatic interaction, a dense layer of cover was formed on the GO surface. GCD and CV tests in the three electrode system showed that the specific capacitance value of GO/PPy reached 468Fg-1 at the current density of 0.5Ag-1, higher than the specific capacitance value (267Fg-1) of the single PPy electrode. Moreover, the synergy between GO and PPy. The multiplier and cyclic stability of GO/PPy have been greatly improved. Thus, the capacitive performance of the GO/PPy two composite obtained by PPy and GO is enhanced. Three, the synthesis and capacitance of the graphene oxide / carbon quantum dots / polypyrrole three composite materials and the study of the capacitance properties of the composites are used respectively by the microwave assisted pyrolysis method. Carbon quantum dots (CDs), graphene oxide / carbon quantum dots (GO/CDs) two elements and three elements of graphene oxide / carbon quantum dots / polypyrrole (GO/CDs/PPy) are synthesized by thermal method and in situ polymerization. By introducing CDs between GO nanoscale and PPy layer, the electronic transmission of three element composite materials can be enhanced and the internal resistance of the electrode is reduced. In addition, the CDs with high specific surface area can enhance the interface property between the GO, CDs and PPy three, thereby increasing the dielectric constant of the three element composite. Under the current density of 0.5 A g-1, GO/CDs/PPy presents a specific capacitance of 576 Fg-1, which is assembled into a symmetric supercapacitor and can be obtained at the power density of 250Wkg-1. The maximum energy density is 30.1 Wh kg-1.. It is more important that the three element composite has a high specific capacitance after 5000 charge discharge, and shows excellent cyclic stability. In order to evaluate the practical application value of the electrode material, we series the 5 supercapacitors into a simple module, and it is found that only 59 can be charged for 17 seconds. The results show that CDs plays an important role in improving the capacitive performance of the GO/CDs/PPy three element composite. The constructed double layer capacitance / pseudo capacitor hybrid supercapacitor has high energy density and excellent cyclic stability, which has potential market prospects.

【學(xué)位授予單位】：安徽大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TB33;TM53

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本文編號(hào)：1817584