本文關(guān)鍵詞：氮摻雜石墨烯及其復(fù)合材料相關(guān)性能的研究　出處：《北京交通大學(xué)》2017年博士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 石墨烯 氮摻雜 第一性原理 鋰離子電池

【摘要】：石墨烯自從在2004年被首次制備出來,在短短幾年內(nèi),就成為材料科學(xué)領(lǐng)域的研究熱點。石墨烯也因其優(yōu)異的物理、化學(xué)性能而被應(yīng)用到諸如儲能、化工、光電、傳感等許多領(lǐng)域,石墨烯產(chǎn)業(yè)目前也處于快速發(fā)展和成熟的過程中。隨著應(yīng)用的進一步深入,未經(jīng)改性的純石墨烯已經(jīng)很難滿足需求,比如:本征石墨烯的零帶隙特性,限制了其在半導(dǎo)體領(lǐng)域的應(yīng)用;石墨烯自身的電化學(xué)性能無法完全滿足新一代儲能器件的要求,需要和特定材料進行復(fù)合以提升綜合性能。摻雜是改變石墨烯特性最有效的手段之一。本論文從理論上研究了包括氮原子在內(nèi)的幾種非金屬原子插層對石墨烯的性能調(diào)控作用,還分別實驗制備了氮摻雜石墨烯和二氧化錫納米晶體以及磷酸釩鋰納米顆粒的復(fù)合材料,測試了復(fù)合材料的性能。本論文主要研究內(nèi)容如下:(1)現(xiàn)有石墨烯摻雜的理論研究主要關(guān)注替代摻雜和缺陷修飾,本論文對石墨烯插層摻雜的理論研究進行了有效補充,提出了SiC (0001)面上外延生長的雙層石墨烯被包括氮原子在內(nèi)的非金屬原子插層的模型,采用第一性原理分析的方法研究了其能帶特性和界面磁性。為了作對比,我們先分別研究了氟,氯,氧,氮原子可能的插層方式以及插層前后的能帶和界面磁性等的變化,然后匯總進行了橫向比較。發(fā)現(xiàn)通過增加氟原子的吸附濃度,可以精確地將體系從n型摻雜調(diào)制到電中性,再調(diào)制到p型摻雜,同時界面磁性也跟著發(fā)生變化。氯摻雜特性和氟摻雜類似。氧原子修飾則能產(chǎn)生p型摻雜。氮原子修飾能給石墨烯打開一個小的帶隙。該部分研究對石墨烯性能調(diào)控具有一定價值。(2)采用水合肼蒸氣還原的方法,制備出了二氧化錫納米顆粒晶體和氮摻雜石墨烯的復(fù)合材料,并用X射線衍射圖,XPS能譜圖,透射電鏡圖,拉曼光譜等進行了表征,研究了復(fù)合材料的形貌、微觀結(jié)構(gòu)、成分。二氧化錫納米顆粒負極雖然具有較高的理論容量,但循環(huán)穩(wěn)定性極差。為了探究氮摻雜石墨烯對二氧化錫電化學(xué)性能的影響,我們將該復(fù)合材料和對照組的二氧化錫納米顆粒制備成扣式電池負極,做了比容量和循環(huán)性能等方面的測試。相對二氧化錫基負極而言,該復(fù)合材料負極具有更高的比容量和更穩(wěn)定的循環(huán)性能。(3)實驗并示范了一種能快速制備氮摻雜石墨烯和碳包覆磷酸釩鋰納米顆粒復(fù)合材料的簡單方法。為了作對比,還制備了石墨烯和碳包覆的磷酸釩鋰納米顆粒的復(fù)合材料,以及碳包覆的磷酸釩鋰納米顆粒材料。表征了三組樣品的形貌、微觀結(jié)構(gòu)和成分。并對三組正極材料進行了循環(huán)性能、倍率性能、長周期穩(wěn)定性等測試,測試結(jié)果的比較可以進一步認識氮摻雜對石墨烯的性能影響,以及氮摻雜石墨烯對磷酸釩鋰納米顆粒的電化學(xué)性能的影響。該部分研究對于磷酸釩鋰正極材料在高倍率下容量偏低的問題,以及循環(huán)性能的提升均提出了解決方案。
[Abstract]:Since graphene was first prepared in 2004, in a few years, it has become a research hotspot in the field of materials science. Graphene is also due to their excellent physical and chemical properties and has been applied in energy storage, chemical industry, optoelectronics, sensor and so many fields, graphene industry is also in rapid development and mature in the process. With the further application, without the pure graphene modified has been difficult to meet the demand, such as: zero band gap intrinsic graphene, which limits its application in the semiconductor field; the electrochemical properties of graphene itself can not fully meet the requirements of the new generation device, need and the specific composite materials to enhance the comprehensive performance. Doping is one of the most effective means to change the graphene characteristics. This thesis studies several nitrogen atoms, including non metal atom Intercalation Performance regulation of graphene Also, respectively. Experiment of composite nitrogen doped graphene oxide and tin nano crystal two and lithium vanadium phosphate nanoparticles were prepared. The properties of the composites were tested. The main research contents of this paper are as follows: (1) the theory research mainly focus on the doping and defects of existing modified graphene doped, theoretical study of this thesis intercalation doping on graphene were effectively, put forward the SiC (0001) non metal atom bilayer graphene epitaxial growth on the surface of the nitrogen atoms are included, inserted layer model, adopting the analysis method of the first principle of the band characteristics and interface magnetic. For comparison, we first were studied by fluorine, chlorine, oxygen, and nitrogen atoms may intercalation and intercalation before and after the changes of band and magnetic interface, and then summarized the horizontal comparison. Found by increasing the adsorption concentration of fluorine,. It will system from the N type doping modulation to the electrically neutral, then modulated to p type doping, while the interface magnetic changes. Chlorine doping characteristics and fluorine doping. Similar oxygen atoms can be modified P type doping. The nitrogen atom modification can open a small gap to the graphene. This part of research this has a certain value on the graphene performance regulation. (2) by using the method of hydrazine vapor reduction, prepared the composite two tin oxide nanoparticle crystals and nitrogen doped graphene, and using X ray diffraction and XPS spectrum, transmission electron microscope, Raman spectra were characterized, research the morphology, microstructure, composition of two tin oxide nanoparticles as anode. Although it has high theoretical capacity, but capacityfading. In order to study the influence of nitrogen doped graphene on the electrochemical properties of tin oxide two, the composite material and two in the control group Tin oxide nanoparticles prepared by button battery cathode, the specific capacity and cycle performance and other aspects of the test. The relative two tin oxide based anode, the composite electrode has higher capacity and more stable cycle performance. (3) the experiment and demonstration of a simple method for rapid preparation of nitrogen the doped graphene and carbon coated lithium vanadium phosphate nano particle composite material. For comparison, also prepared composite materials lithium vanadium phosphate nanoparticles and graphene coated with carbon, and carbon coated lithium vanadium phosphate nanoparticles. The characterization of the three groups of samples morphology, microstructure and composition. The three group of cathode material cycle performance, rate capability, long cycle stability test, comparison of test results to further understand the effects of nitrogen doping on the properties of graphene, and electrochemical nitrogen doped graphene lithium vanadium phosphate nanoparticles The influence of performance is studied. This part puts forward a solution to the problem of low capacity and high cycle performance of vanadium phosphate cathode material.

【學(xué)位授予單位】：北京交通大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：TM912;TB33

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本文編號：1409710