石墨烯基材料的制備及儲(chǔ)鋰性能研究
發(fā)布時(shí)間：2019-01-14 08:36
【摘要】：鋰離子電池以其高的能量密度、長(zhǎng)的循環(huán)壽命、環(huán)境友好、無(wú)記憶效應(yīng)等諸多優(yōu)點(diǎn),被廣泛應(yīng)用于便攜式移動(dòng)電子設(shè)備中。而隨著電子設(shè)備技術(shù)的快速發(fā)展,人們對(duì)鋰離子電池性能提出了更高的要求。目前傳統(tǒng)商業(yè)化的負(fù)極材料石墨較低的比容量(372mAh g-1)已經(jīng)不能滿足鋰離子電池發(fā)展的需求。因此有必要開(kāi)發(fā)新型的負(fù)極材料。所以本文針對(duì)鋰離子電池研究體系,以負(fù)極材料為研究對(duì)象,合成了鉍/氮摻雜石墨烯納米復(fù)合材料,并對(duì)其儲(chǔ)鋰性能進(jìn)行了系統(tǒng)的研究;在此基礎(chǔ)上,針對(duì)傳統(tǒng)電極材料不能彎曲,不具備柔性的特點(diǎn),制備出了柔性功能化的三維石墨烯泡沫并將其用于鋰離子電池負(fù)極材料,研究了其電化學(xué)性能。具體研究?jī)?nèi)容如下:(1)采用氣液界面反應(yīng)和快速熱處理的方法合成了鉍l氮摻雜石墨烯納米復(fù)合材料,并將其用于鋰離子電池的負(fù)極材料,研究了其電化學(xué)性能。該復(fù)合材料具有高達(dá)522 mAh g-1的比容量,即使在不同的電流密度下循環(huán)50次后,其比容量仍高達(dá)386 mAh g-1。在1000 mA g-1的大電流密度下,該復(fù)合材料的可逆比容量仍保持在218 mAh g-1。與已報(bào)道的鉍基復(fù)合材料相比,展現(xiàn)了更加優(yōu)異的電化學(xué)性能。其優(yōu)異的電化學(xué)性能主要得益于氮摻雜石墨烯的高的導(dǎo)電性和鉍納米粒子與氮摻雜石墨烯之間的協(xié)同效應(yīng)。(2)采用一種簡(jiǎn)單、溫和的途徑合成了具有一體化結(jié)構(gòu)、自支撐的功能化的三維石墨烯泡沫,具體方法是以可再生的生物質(zhì)資源葡萄糖為碳源,通過(guò)模板輔助的水熱碳化反應(yīng)來(lái)制備。整個(gè)制備過(guò)程,綠色環(huán)保,簡(jiǎn)單易行,而且成本低廉。此外,制備的功能化的三維石墨烯泡沫具有優(yōu)異的柔性,我們將其直接用作柔性電極材料,組裝成紐扣型的鋰離子電池,通過(guò)恒流充放電測(cè)試、循環(huán)伏安測(cè)試等方法初步研究了其電化學(xué)性能。研究結(jié)果表明,在5 mA g-1的小電流密度下,其比容量為22 mAh g-1。由于材料中含氧官能團(tuán)的存在致使其導(dǎo)電性不佳和材料本身性能的影響,導(dǎo)致其儲(chǔ)鋰性能并不理想。盡管其比容量不理想,但該材料具有優(yōu)異的可折柔性,可以將其發(fā)展作為柔性集流體材料。(3)分別采用高溫還原、水合肼還原和乙二醇還原的三種還原方式對(duì)功能化的三維石墨烯泡沫進(jìn)行還原,并對(duì)還原之后的產(chǎn)物分別進(jìn)行了 SEM、FITR、Raman的表征分析以及彎曲性能測(cè)試。通過(guò)對(duì)比分析,結(jié)果表明,采用水合肼還原方式對(duì)功能化的三維石墨烯泡沫進(jìn)行還原可以得到還原效果較好,適合作為柔性集流體的三維石墨烯泡沫材料。
[Abstract]:Li-ion batteries are widely used in portable mobile electronic devices due to their high energy density, long cycle life, environment-friendly, no memory effect and many other advantages. With the rapid development of electronic equipment technology, the performance of lithium ion batteries has been put forward higher requirements. At present, the low specific capacity of graphite (372mAh g-1), a traditional commercial anode material, can no longer meet the needs of lithium ion battery development. Therefore, it is necessary to develop new negative electrode materials. Therefore, in this paper, bismuth / nitrogen-doped graphene nanocomposites were synthesized and their lithium storage properties were studied systematically, aiming at the lithium ion battery research system, taking the anode material as the research object. On this basis, the flexible functional three-dimensional graphene foam was prepared and used as anode material for lithium ion battery. The electrochemical properties of the three dimensional graphene foam were studied. The main contents are as follows: (1) Bi-1-N-doped graphene nanocomposites were synthesized by gas-liquid interfacial reaction and rapid heat treatment, and were used as anode materials for lithium ion batteries, and their electrochemical properties were studied. The specific capacity of the composite is up to 522 mAh g ~ (-1). Even after 50 cycles at different current density, the specific capacity of the composite is as high as 386 mAh g ~ (-1). At a high current density of 1000 mA g ~ (-1), the reversible specific capacity of the composite remains at 218 mAh g ~ (-1). Compared with the reported bismuth matrix composites, the electrochemical properties of the composites are more excellent. Its excellent electrochemical properties are mainly due to the high conductivity of nitrogen-doped graphene and the synergistic effect between bismuth nanoparticles and nitrogen-doped graphene. Self-supporting functional three-dimensional graphene foam was prepared by template assisted hydrothermal carbonization using renewable biomass resource glucose as carbon source. The whole preparation process is environmental friendly, simple and easy to use, and low in cost. In addition, the functionalized three-dimensional graphene foam has excellent flexibility. It is directly used as a flexible electrode material to assemble a button type lithium ion battery, which is tested by constant current charge and discharge. The electrochemical performance was studied by cyclic voltammetry. The results show that the specific capacity is 22 mAh g ~ (-1) at the low current density of 5 mA g ~ (-1). Due to the existence of oxygen functional groups in the materials, the conductivity of the materials is not good and the properties of the materials themselves are affected, which leads to the poor lithium storage performance of the materials. Although its specific capacity is not ideal, the material has excellent flexural flexibility and can be developed as a flexible fluid collecting material. (3) reduction at high temperature, The three reduction methods of hydrazine hydrate and ethylene glycol were used to reduce the functionalized three dimensional graphene foam. The products after reduction were characterized by SEM,FITR,Raman and the bending properties were tested. The results show that the reduction effect of functional three dimensional graphene foam can be obtained by hydrazine hydrate reduction method, which is suitable for the flexible fluid collection of three dimensional graphene foam material.
【學(xué)位授予單位】：昆明理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類(lèi)號(hào)】：TM912
本文編號(hào)：2408524
[Abstract]:Li-ion batteries are widely used in portable mobile electronic devices due to their high energy density, long cycle life, environment-friendly, no memory effect and many other advantages. With the rapid development of electronic equipment technology, the performance of lithium ion batteries has been put forward higher requirements. At present, the low specific capacity of graphite (372mAh g-1), a traditional commercial anode material, can no longer meet the needs of lithium ion battery development. Therefore, it is necessary to develop new negative electrode materials. Therefore, in this paper, bismuth / nitrogen-doped graphene nanocomposites were synthesized and their lithium storage properties were studied systematically, aiming at the lithium ion battery research system, taking the anode material as the research object. On this basis, the flexible functional three-dimensional graphene foam was prepared and used as anode material for lithium ion battery. The electrochemical properties of the three dimensional graphene foam were studied. The main contents are as follows: (1) Bi-1-N-doped graphene nanocomposites were synthesized by gas-liquid interfacial reaction and rapid heat treatment, and were used as anode materials for lithium ion batteries, and their electrochemical properties were studied. The specific capacity of the composite is up to 522 mAh g ~ (-1). Even after 50 cycles at different current density, the specific capacity of the composite is as high as 386 mAh g ~ (-1). At a high current density of 1000 mA g ~ (-1), the reversible specific capacity of the composite remains at 218 mAh g ~ (-1). Compared with the reported bismuth matrix composites, the electrochemical properties of the composites are more excellent. Its excellent electrochemical properties are mainly due to the high conductivity of nitrogen-doped graphene and the synergistic effect between bismuth nanoparticles and nitrogen-doped graphene. Self-supporting functional three-dimensional graphene foam was prepared by template assisted hydrothermal carbonization using renewable biomass resource glucose as carbon source. The whole preparation process is environmental friendly, simple and easy to use, and low in cost. In addition, the functionalized three-dimensional graphene foam has excellent flexibility. It is directly used as a flexible electrode material to assemble a button type lithium ion battery, which is tested by constant current charge and discharge. The electrochemical performance was studied by cyclic voltammetry. The results show that the specific capacity is 22 mAh g ~ (-1) at the low current density of 5 mA g ~ (-1). Due to the existence of oxygen functional groups in the materials, the conductivity of the materials is not good and the properties of the materials themselves are affected, which leads to the poor lithium storage performance of the materials. Although its specific capacity is not ideal, the material has excellent flexural flexibility and can be developed as a flexible fluid collecting material. (3) reduction at high temperature, The three reduction methods of hydrazine hydrate and ethylene glycol were used to reduce the functionalized three dimensional graphene foam. The products after reduction were characterized by SEM,FITR,Raman and the bending properties were tested. The results show that the reduction effect of functional three dimensional graphene foam can be obtained by hydrazine hydrate reduction method, which is suitable for the flexible fluid collection of three dimensional graphene foam material.
【學(xué)位授予單位】：昆明理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類(lèi)號(hào)】：TM912
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