本文選題：磁赤鐵礦 + 多孔材料�。� 參考：《青島科技大學(xué)》2017年碩士論文

【摘要】：鋰離子電池具有高的能量密度,高充放電效率,壽命長(zhǎng)以及無(wú)記憶效應(yīng)等優(yōu)點(diǎn),已成為滿足未來(lái)經(jīng)濟(jì)社會(huì)可持續(xù)發(fā)展的高能電池之一,電極材料是其發(fā)揮這一效能的關(guān)鍵。然而前商業(yè)上普遍使用的石墨負(fù)極材料,理論容量較低,無(wú)法滿足高能量應(yīng)用的要求,如汽車動(dòng)力電源、智能電網(wǎng)等。因此,人們致力于研究新的電池材料來(lái)滿足未來(lái)鋰離子電池的發(fā)展需求。就這一點(diǎn)而言,過(guò)渡金屬氧化物及過(guò)渡金屬硫化物具有高的理論比容量,成為近年來(lái)負(fù)極材料的研究熱點(diǎn)。其中,由于鐵氧化物及硫化物具有成本低廉,生態(tài)友好,儲(chǔ)量豐富以及容量高等優(yōu)點(diǎn),得到廣泛的關(guān)注。本研究主要在于研究鐵的氧化物和硫化物用做鋰離子電池負(fù)極材料的電化學(xué)性能。主要研究?jī)?nèi)容如下:(1)由多孔納米帶組裝成的磁赤鐵礦微米結(jié)構(gòu)用于鋰離子電池負(fù)極材料通過(guò)一種簡(jiǎn)單有效、自下而上的方法合成金屬有機(jī)物前驅(qū)體模板,后對(duì)其進(jìn)行熱處理得到具有由納米晶組成的多孔納米帶進(jìn)而組裝成多級(jí)微米結(jié)構(gòu)。這種合成方法簡(jiǎn)單易行,成本低,適于大規(guī)模生產(chǎn)。在鋰離子電池中作為負(fù)極材料,具有高的可逆容量,當(dāng)電流密度為0.1 A·g-1時(shí),放電比容量達(dá)到1344 mAh·g-1,在5 A·g-1時(shí),放電容量達(dá)到408 mAh·g-1,以及良好的循環(huán)穩(wěn)定性,1 A·g-1下,進(jìn)行100次充放電后,容量仍可保持700 mAh·g-1。這種多級(jí)多孔結(jié)構(gòu)提高了離子的運(yùn)輸效率,緩解在充放電過(guò)程中的體積變化而造成的結(jié)構(gòu)破壞。(2)采用固相硫化法制備FeS/C,并用于鋰離子電池負(fù)極材料通過(guò)原位硫化MOF-Fe的方法,制備出梭形FeS/C微納米結(jié)構(gòu)材料,在電流密度為0.1 A·g-1時(shí),進(jìn)行500次充放電,放電容量仍可保持744 mAh·g-1,具有較好的循環(huán)穩(wěn)定性能,在10 A·g-1時(shí),放電容量可達(dá)到322.2 mAh·g-1,良好的倍率性能,這主要是由于碳的摻雜以及多級(jí)多孔的微納米結(jié)構(gòu)不僅縮短離子運(yùn)輸路徑提高離子傳輸速度,而且有利于結(jié)構(gòu)保持穩(wěn)定,從而使材料表現(xiàn)出優(yōu)異的電化學(xué)性能。(3)Fe_3O_4@C材料的制備,并用于鋰離子電池負(fù)極材料的電化學(xué)性能研究。為改善鐵基氧化物的缺點(diǎn),將鐵基氧化物的結(jié)構(gòu)進(jìn)行設(shè)計(jì),制備出Fe_3O_4@C具有核殼結(jié)構(gòu)的材料,碳的包覆結(jié)構(gòu)既可以提高材料的導(dǎo)電性能有可以保證充放電過(guò)程中結(jié)構(gòu)的穩(wěn)定性。實(shí)驗(yàn)結(jié)果顯示:Fe_3O_4@C的電化學(xué)性能相比Fe_3O_4得到很大改善,因此Fe_3O_4@C具有更好的電化學(xué)性能。當(dāng)電流密度為0.1 A·g-1時(shí),可逆容量為788.2 mAh·g-1,在10 A·g-1時(shí),可逆容量達(dá)到358.8mAh·g-1,具有良好的倍率性能。在0.1 A·g-1經(jīng)過(guò)500次循環(huán)容量仍可以保持良好,具有優(yōu)異的循環(huán)穩(wěn)定性。
[Abstract]:Li-ion batteries have many advantages, such as high energy density, high charge-discharge efficiency, long life and no memory effect. They have become one of the high energy batteries to meet the sustainable development of economy and society in the future. Electrode materials are the key to play this role. However, the theoretical capacity of graphite anode materials, which are widely used in the former commercial field, is low and can not meet the requirements of high-energy applications, such as automobile power supply, smart grid, etc. Therefore, people devote themselves to the research of new battery materials to meet the development needs of lithium ion batteries in the future. In this respect, transition metal oxides and transition metal sulfides have high theoretical specific capacity and have become a hot research topic of anode materials in recent years. Among them, iron oxides and sulfides have attracted wide attention due to their advantages of low cost, ecological friendliness, rich reserves and high capacity. The main purpose of this study is to study the electrochemical performance of iron oxides and sulfides as anode materials for lithium ion batteries. The main research contents are as follows: (1) Magneto-hematite microstructures assembled from porous nanobelts are used as cathode materials for lithium ion batteries through a simple and effective bottom-up method to synthesize metal organic precursor templates. After heat treatment, porous nanoribbons with nanocrystalline structure were obtained and assembled into multilevel micron structures. This synthetic method is simple and feasible, low cost and suitable for mass production. When the current density is 0. 1 A g ~ (-1), the discharge specific capacity is 1344 mAh g ~ (-1), the discharge capacity is 408 mAh g ~ (-1) at 5 A g ~ (-1), and the good cycle stability is 1 A g ~ (-1). After 100 times of charge and discharge, the capacity can still be maintained at 700 mAh g ~ (-1). This multilevel porous structure can improve the transport efficiency of ions and alleviate the structural damage caused by volume change during charge and discharge. FES / C is prepared by solid phase vulcanization method, and used for lithium ion battery anode material through in-situ vulcanization of MOF-Fe. The fusiform FeS/C microstructures were prepared. When the current density was 0.1A g ~ (-1), the discharge capacity could be maintained at 744 mAh g ~ (-1), and the discharge capacity could reach 322.2 mAh g ~ (-1) at 10 Ag ~ (-1). This is mainly due to the fact that carbon doping and multilevel porous microstructures not only shorten the ion transport path and improve the ion transport speed, but also help to keep the structure stable, thus making the materials exhibit excellent electrochemical properties. It is also used to study the electrochemical performance of cathode materials for lithium ion batteries. In order to improve the defects of iron based oxides, the structure of iron based oxides was designed, and the core-shell structure of Fe_3O_4@C was prepared. The coating structure of carbon can not only improve the conductivity of the materials, but also guarantee the stability of the structure during charging and discharging. The results show that the electrochemical performance of Fe_3O_4@C is better than that of Fe_3O_4. When the current density is 0. 1 A g ~ (-1), the reversible capacity is 788.2 mAh g ~ (-1), and the reversible capacity is up to 358.8mAh g ~ (-1) when the current density is 10 A g ~ (-1). After 500 cycles at 0.1 A g ~ (-1), the capacity can be maintained well and has excellent cycle stability.
【學(xué)位授予單位】：青島科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TM912

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