本文關(guān)鍵詞： 超級電容器 電極材料 多孔碳 水溶性殼聚糖 電化學性能　出處：《西北大學》2015年碩士論文　論文類型：學位論文

【摘要】：超級電容器也叫做電化學電容器,由于一般情況下它們的比電容較高、循環(huán)穩(wěn)定性好、工作原理比較容易還有功率密度也比較高等特點而漸漸成為人們關(guān)注的熱點,同時,它也與二次電池聯(lián)用而廣泛的被科研人員探索。由于極大多數(shù)具有高比表面積的多孔碳的電化學性能都非常卓越優(yōu)良,而且其成本也相對較低,多孔碳材料已漸漸成為科學家們使用最廣泛的一種電極材料。而使用過渡金屬氧化物與碳材料復合作為電極材料時,會進一步提升其比電容。由于生物質(zhì)種類眾多,含量非常豐富并且成本低廉,屬于可再生資源,可以對其進行循環(huán)利用和開發(fā)。同時,生物質(zhì)是自然界存在的可再生的碳載體,人們在將其轉(zhuǎn)化為新式的炭材料方向做了很多工作,所以說生物質(zhì)在制備碳材料方面擁有廣闊的發(fā)展空間。最近,多孔碳材料的制備很多都是使用生物質(zhì)為原材料,這漸漸變成了一個熱門的研究課題,利用生物質(zhì)作為原料,不僅可以節(jié)約成本,而且可以減削由大量廢棄生物質(zhì)焚燒給環(huán)境帶來的污染問題。生物質(zhì)的種類多種多樣,而殼聚糖是自然界含量除了纖維素以外含量最高的多糖。除了殼聚糖以外,蓮蓬殼也是一種重要的生物質(zhì),蓮蓬殼除了少部分入藥以外,大部分被丟棄成為垃圾或作為低熱值燃料,造成了巨大的能源浪費。本文的工作是選用水溶性的殼聚糖以及蓮蓬殼分別為碳源,通過碳化最后得到了多孔碳基電容器電極材料,實驗內(nèi)容主要為：(1)采用直接水熱碳化水溶性殼聚糖得到片狀碳材料的中間體,并進一步對得到的產(chǎn)物進行高溫碳化,得到片狀多孔碳材料。結(jié)果表明：通過在800℃下碳化后得到的多孔碳材料的比電容為166 F/g,在2000次循環(huán)后其比容量約為之前的98%。(2)采用水熱發(fā)通過原位復合得到了碳/Fe3O4復合物,并進一步對得到的產(chǎn)物進行高溫碳化,得到了碳與過渡金屬氧化物的復合材料。結(jié)果表明,在0.05 A g-1的電流密度下,多孔碳/Fe3O4的比電容可達到299 F g-1,當電流密度增大為2 A g-1后,比電容下降了20.7%。多孔碳/Fe3O4具有良好的充放電循環(huán)穩(wěn)定性,在循環(huán)2000次后它的比容量仍保持之前的84%。(3)以蓮蓬殼為原料,KOH為活化劑,采用碳化活化兩步方法來制備以生物質(zhì)為源的碳材料。此外,我們還探討了加入KOH的量和活化溫度對產(chǎn)物的比表面積和比容量的影響。我們發(fā)現(xiàn)：當活化劑與蓮蓬殼的質(zhì)量比為4：1時,樣品的比表面積達到最大(2961m2g-1),0.5Ag-1電流密度下的比容量可達345 F g-1。另外,我們在工作中還研究了不同活化溫度和不同活化劑用量對產(chǎn)物以及其電化學性能的影響。
[Abstract]:Supercapacitors, also called electrochemical capacitors, have become the focus of attention because of their high specific capacitance, good cycle stability, easy working principle and high power density. It has also been extensively explored by researchers in conjunction with secondary batteries. Because most of the porous carbon with high specific surface areas has excellent electrochemical performance and its cost is relatively low, Porous carbon materials have gradually become the most widely used electrode materials by scientists. When the transition metal oxides and carbon materials are used as electrode materials, the specific capacitance is further enhanced. Rich in content and low in cost, it is a renewable resource that can be recycled and exploited. At the same time, biomass is a renewable carbon carrier that exists in nature. A lot of work has been done to turn it into new carbon materials, so biomass has a lot of room for development in the preparation of carbon materials. Recently, many porous carbon materials have been prepared using biomass as raw materials. This has gradually become a hot research topic. Using biomass as raw material can not only save costs, but also reduce the pollution caused by the incineration of a large amount of waste biomass. There are many kinds of biomass. In addition to chitosan, the shell of lotus is also an important biomass. Most of them were discarded as garbage or as low calorific value fuel, which resulted in a huge waste of energy. In this paper, water-soluble chitosan and lotus shell were selected as carbon source, and the porous carbon capacitor electrode materials were obtained by carbonization. The main content of the experiment is: (1) the intermediate of flake carbon material is obtained by direct hydrothermal carbonization of water-soluble chitosan, and the obtained products are further carbonized at high temperature. The results show that the specific capacitance of the porous carbon materials obtained by carbonization at 800 鈩，

本文編號：1553033