【摘要】：鋰離子電池作為新興儲能電池,被廣泛研究應(yīng)用于電子設(shè)備和混合動力電動車。而對于鋰電的研究主要是集中在電極方面,其關(guān)鍵是尋找高容量,高能量密度的電池材料。目前已經(jīng)商業(yè)化的鋰電負極材料主要是石墨材料,其電導(dǎo)率高,但理論容量低(372 m Ah g-1),因此關(guān)于負極材料的研究開始轉(zhuǎn)向其他材料。目前發(fā)現(xiàn)金屬硫化物擁有非常高的理論容量,如Mo S2的理論容量為(670 m Ah g-1)。但是由于其存在電導(dǎo)率較低、在充放電過程會有體積坍塌現(xiàn)象,而這些問題主要是從以下兩個方面來解決,(1)合成特殊的納米結(jié)構(gòu)來支撐材料不坍縮;(2)通過和其他納米材料(如石墨烯、金屬氧化物以及金屬硫化物)復(fù)合,通過協(xié)同效應(yīng),來提高整體材料的比容量以及抵抗抗體積效應(yīng)的能力。本章主要是通過上述兩個方面來提高金屬硫化物在鋰離子電池中的各方面性能,主要內(nèi)容如下:1、利用犧牲模板法合成由二維Mo S2納米片組裝的三維Mo S2納米管,通過對納米管形成過程的研究,探索其這種特殊納米結(jié)構(gòu)的形成機理,并將其制備成電極材料,展現(xiàn)出了優(yōu)秀的電化學(xué)性能。同時還深入研究其在循環(huán)后形貌和組分的變化,進一步闡明整個材料的充放電過程以及性能優(yōu)越性的原因。2、進一步探究了以三氧化鉬為模板制備二硫化鉬方法的普遍適用性,用此方法合成二維Mo S2納米片組裝的多孔Mo S2納米片,并對其進行高溫煅燒,提高其電化學(xué)性能。通過對比煅燒前后多孔Mo S2微納米片和Mo S2納米管的電化學(xué)性能,發(fā)現(xiàn)煅燒后的多孔Mo S2微納米片具有最佳儲鋰性能,同時對循環(huán)后負極材料進行形貌和組分分析表征,分析了煅燒后材料性能優(yōu)越的原因。3、本章通過兩步溶劑熱法合成出Co9S8@Mo S2/r GO三元復(fù)合物材料,其中Mo S2納米片生長在Co9S8的表面,并形成了納米核殼結(jié)構(gòu)。文中探索了鈷和鉬鹽不同負載量的三元復(fù)合材料,同時還合成Co9S8/r GO二元復(fù)合材料,依據(jù)對其以及前兩章二硫化鉬的脫鋰嵌鋰的研究,進一步推測三元復(fù)合材料的脫鋰嵌鋰過程,同時經(jīng)過對二元和三元復(fù)合材料的電化學(xué)性能的對比,突出Co9S8@Mo S2核殼結(jié)構(gòu)的優(yōu)越性。并通過對循環(huán)后負極材料的表征,闡明該三元復(fù)合材料電化學(xué)性能優(yōu)越的原因。
[Abstract]:As a new energy storage battery, lithium ion battery has been widely used in electronic devices and hybrid electric vehicles. The research of lithium is mainly focused on the electrode, the key is to find high capacity, high energy density battery materials. At present, the commercial lithium anode materials are mainly graphite materials with high conductivity but low theoretical capacity (372mAh g-1). Therefore, the research on anode materials has turned to other materials. At present, it has been found that metal sulfides have very high theoretical capacity, such as the theoretical capacity of Mo S2 is (670 mAh / g ~ (-1). However, due to its low conductivity, there will be volume collapse in the charge-discharge process. These problems are solved mainly in the following two aspects: (1) the synthesis of special nanostructures to support the material from collapsing; (2) the synergistic effect of combining with other nanomaterials (such as graphene, metal oxides and metal sulphides). To improve the specific capacity of the whole material and the ability to resist the volume effect. In this chapter, the properties of metal sulfides in lithium ion batteries are improved through the above two aspects. The main contents are as follows: 1. The three-dimensional MoS2 nanotubes assembled by two-dimensional MoS2 nanoplates were synthesized by sacrificial template method. Through the study of the formation process of nanotubes, the formation mechanism of this special nanostructure was explored, and the electrode materials were prepared, showing excellent electrochemical properties. At the same time, the changes of morphology and composition after cycling were also studied, the charge-discharge process of the whole material and the reasons for its performance superiority were further elucidated, and the universal applicability of the method of preparing molybdenum disulfide with molybdenum trioxide as template was further explored. The porous MoS2 nanoparticles were synthesized by this method and calcined at high temperature to improve their electrochemical properties. By comparing the electrochemical properties of the porous MoS2 microchips and MoS2 nanotubes before and after calcination, it was found that the calcined porous MoS2 microchips had the best lithium storage performance, and the morphology and composition of the cyclic anode materials were characterized. In this chapter, Co9S8MoS2 / r go ternary composite material was synthesized by two step solvothermal method. MoS2 nanocrystalline grown on the surface of Co9S8 and formed nanocrystalline core-shell structure. In this paper, ternary composites with different amounts of cobalt and molybdenum salts were investigated. Co9S8 / r go binary composites were also synthesized. Based on the study of the delithium intercalation of molybdenum disulfide and the former two chapters, the delithium intercalation process of the ternary composites was further speculated. At the same time, the advantages of Co9S8MoS2 core-shell structure are highlighted by comparing the electrochemical properties of binary and ternary composites. The reason for the excellent electrochemical performance of the ternary composite was explained by the characterization of the negative electrode material after the cycle.
【學(xué)位授予單位】：安徽師范大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TB383.1;TM912

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