發(fā)布時間：2018-04-10 00:08

  本文選題：金屬有機骨架材料　切入點：鋰離子電池　出處：《中國科學技術大學》2016年碩士論文

【摘要】：隨著現(xiàn)代交通運輸工具如混合動力電動汽車、全電動汽車等的發(fā)展,人們急切需要高能量密度和高功率密度電能存儲裝置(EES)來滿足這些運輸工具的需求。作為新興EES系統(tǒng)的前列,鋰離子、鋰硫電池,超級電容器備受關注,但它們都很難同時滿足較高的能量密度和功率密度、較高的倍率性能、較長的循環(huán)壽命、較高的安全性等所有要求。因此,開發(fā)具有新的化學特性及較高的電化學性能的電極材料并將其用于電能存儲裝置,具有很大的現(xiàn)實意義。金屬有機骨架(MOFs)作為一類多孔結晶材料,通過較強的配位作用將無機、有機單元連接起來,大多數(shù)的無機單元是金屬離子或金屬氧化物,可充當電化學過程中的氧化還原活性位點,而有機配體是很好的碳源,因而MOFs作為電極材料有很大的潛力,尤其最近幾年,MOFs在電化學能量儲存領域中的應用日漸興起并備受關注。在本論文中,我們基于乳液界面聚合,設計制備一種結構可控的金屬有機骨架ZIF-8中空微球,并在此基礎上進行以下三方面的應用研究。一、基于實驗室前期工作,批量制備殼層厚度遞增的三種結構的ZIF-8中空微球,并對其結構與性能進行詳細研究；同時,通過負載Pd納米粒子,用于選擇性催化烯烴的加氫反應,結果顯示,最薄殼層的ZIF-8(T)中空微球具有較高的效率和尺寸選擇性。二、通過高溫碳化金屬有機骨架ZIF-8中空微球,獲得具有較薄殼層、較高含量氮摻雜及較高比表面積的結構可控的多級孔納米中空碳球,可以用于鋰離子電池負極。經(jīng)800℃煅燒所得的薄殼層中空納米碳球?qū)⒏邠降?16.61%)、高比表面積(1038 m2g-1)、多層次的孔徑分布(微、介孔)及可控結構等優(yōu)點相結合,顯示非常優(yōu)異的電化學性能。在較低的電流密度100 mA g-1充放電100圈,可逆比容量高達2047 mAh g-1,保留了第二圈放電比容量的97%,循環(huán)穩(wěn)定性非常好；甚至在較高的電流密度5 A g-1循環(huán)1000圈,可逆比容量也高達879 mAh g-1,顯示卓越的倍率性能。同時,我們詳細分析了碳化溫度和碳球的結構對LIBs電化學性能的影響,進一步豐富金屬有機骨架材料在鋰離子電池負極中的應用。三、嘗試研究碳化金屬有機骨架所得的碳球在鋰硫電池和超級電容器中的應用,結果顯示,與同類碳材料相比,其電化學性能較差,有待進一步改善和研究。
[Abstract]:With the development of modern transportation tools such as hybrid electric vehicles (HEVs) and all-electric vehicles (EVs), high energy density and high power density electric energy storage devices are urgently needed to meet the needs of these vehicles.As the forefront of the emerging EES system, lithium ion, lithium-sulfur batteries and supercapacitors have attracted much attention, but they are difficult to satisfy both high energy density and power density, high rate performance, and long cycle life.Higher safety requirements, etc.Therefore, it is of great practical significance to develop electrode materials with new chemical characteristics and high electrochemical performance and to use them in electric energy storage devices.As a kind of porous crystalline materials, organometal-organic frameworks (MOFs) connect inorganic and organic units through strong coordination. Most of the inorganic units are metal ions or metal oxides.It can act as redox active site in electrochemical process, and organic ligand is a good carbon source, so MOFs has great potential as electrode material.Especially in recent years, MOFs have been widely used in electrochemical energy storage.In this thesis, we designed and prepared a kind of organometallic skeleton ZIF-8 hollow microspheres based on emulsion interfacial polymerization.Firstly, three kinds of ZIF-8 hollow microspheres with increasing shell thickness were prepared in batches, and their structure and properties were studied in detail based on the previous work in laboratory. At the same time, they were used to selectively catalyze the hydrogenation of olefins by loading PD nanoparticles.The results show that the thinnest shell ZIF-8T hollow microspheres have high efficiency and size selectivity.Secondly, ZIF-8 hollow microspheres with thin shell layer, high nitrogen content doping and high specific surface area were obtained by carbonized metal-organic skeleton hollow microspheres at high temperature, which can be used as negative electrode of lithium ion battery.The hollow hollow carbon spheres calcined at 800 鈩，

本文編號：1728772