石墨烯的化學插層法制備及其在超級電容器中的應用
發(fā)布時間:2018-04-23 03:24
本文選題:石墨烯 + 化學插層法 ; 參考:《蘭州理工大學》2014年碩士論文
【摘要】:石墨烯是一種新型二維炭材料,其諸多優(yōu)異的理化性質引起世界各國的廣泛關注,科學家們發(fā)現(xiàn)石墨烯在微納電子器件、高靈敏傳感器、功能復合材料、儲能、催化等領域有著非常廣闊的應用前景。然而,石墨烯功能材料尚未走進尋常百姓生活,一個主要原因是當前尚未能實現(xiàn)高質量石墨烯的宏量制備;瘜W插層法具有工藝簡單、條件溫和以及產品結構缺陷少等顯著特點,這些優(yōu)勢天然地有利于實現(xiàn)石墨烯的宏量制備;超級電容器是一種性能介于二次電池和傳統(tǒng)電容器之間的新型儲能裝置,具有比二次電池更高的功率密度,比傳統(tǒng)電容器更高的能量密度。超級電容器因其功率密度高、循環(huán)壽命長、工作溫度范圍寬、綠色環(huán)保無污染等優(yōu)點受到廣泛關注,石墨烯超大的比表面積、良好的導電性以及機械強度等優(yōu)點,在超級電容器領域顯示出巨大的潛力:本文以此作為切入點,一方面以成本低廉、工藝簡單、產品高品質為技術要求設計新的石墨烯制備方法,另一方面以石墨烯作為超級電容器電極材料,研究比較哪些因素對超級電容器性能的影響是主要的哪些是次要的。取得的主要成果包括: 一、設計了一種改進的化學插層法,以(NH4)2S2O8、H2SO4和H2O2為原料,實現(xiàn)了常溫下天然石墨在插層反應的同時進行充分地膨脹,省去了當前化學插層法中800℃以上高溫或微波輻照這一必要條件,從而降低了成本,簡化了工藝。經表征,制得的石墨烯具有良好的品質。 二、基于化學插層法基本原理,提出“分子鏟”剝離制備法,即先將天然石墨通過混酸法制成酸插層石墨(也叫可膨脹石墨),利用芐胺分子上顯堿性的氨基與酸插層石墨層間的酸性基團由于酸堿中和而形成的“趨向力”,尺寸較大的芐胺分子就像“鏟子”一樣將石墨一層層“鏟開”得到石墨烯片。再將其分散到DMF中用真空抽濾法制成石墨烯透明導電膜,經酸處理和空氣中退火后,測得其在80%透光度條件下方塊電阻值最低能達到350Ω/sq。 三、通過改進的Hummer法制備氧化石墨烯,在不同溫度的氬氣中還原得到一系列熱還原氧化石墨烯(T-RGO),將其作為超級電容器電極材料。運用電化學分析測試手段比較了比表面積、材料導電性和表面含氧官能團三個因素對電容性能影響的大小結果表明,石墨烯表面含氧官能團對其電容性能的影響要遠大于導電性和比表面積的影響。這使我們以后在設計制備超級電容器等儲能設備用石墨烯電極材料時更加有針對性。
[Abstract]:Graphene is a new two-dimensional carbon material, and its excellent physical and chemical properties have attracted worldwide attention. Scientists have found graphene in micro and nano electronic devices, high sensitivity sensors, functional composites, energy storage. Catalysis and other fields have a very broad application prospects. However, graphene functional materials have not yet entered the lives of ordinary people, one of the main reasons is that the high quality graphene macroscopical preparation has not been realized yet. The chemical intercalation method is characterized by simple process, mild conditions and less defects in the product structure. These advantages are naturally beneficial to the macrosynthesis of graphene. Supercapacitor is a new type of energy storage device with performance between secondary battery and conventional capacitor. It has higher power density than secondary battery and higher energy density than traditional capacitor. Because of its high power density, long cycle life, wide range of working temperature, environmental protection and no pollution, super capacitor has many advantages, such as large specific surface area of graphene, good electrical conductivity and mechanical strength, etc. It shows great potential in the field of supercapacitors. On the one hand, a new preparation method of graphene is designed according to the requirements of low cost, simple process and high quality of products. On the other hand, graphene is used as electrode material of supercapacitor to study which factors affect the performance of supercapacitor. The main results achieved include: Firstly, an improved chemical intercalation method was designed, using NH _ 4N _ 2S _ 2O _ 8 H _ 2SO _ 4 and H2O2 as raw materials, the natural graphite was fully expanded at room temperature while intercalation reaction. The necessary condition of high temperature above 800 鈩,
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