本文選題：鋰離子電池 + 硅/聚苯胺復(fù)合材料　； 參考：《重慶大學(xué)》2014年碩士論文

【摘要】：硅因具有高的理論容量（4200mAh/g）和豐富的資源有望成為替代石墨負(fù)極的候選材料之一。但是硅負(fù)極材料低的導(dǎo)電率、嚴(yán)重的體積效應(yīng)和差的循環(huán)穩(wěn)定性等缺點，嚴(yán)重制約了其商業(yè)化應(yīng)用。碳材料是離子和電子的混合導(dǎo)體，在充放電過程中體積變化小，且具有良好的延展性和彈性，可以作為硅負(fù)極材料的“緩沖基體”。此外，兩者的嵌鋰電位相近，因此，結(jié)合兩者的優(yōu)點有望制備出具有高容量和良好循環(huán)性能的新型鋰離子電池材料。 本研究分別采用苯胺和淀粉為碳源，納米硅為硅源，并通過不同的制備方法制備硅/碳復(fù)合負(fù)極材料。 （1）以納米硅和苯胺為原料，通過乳液聚合和高溫?zé)峤鈨刹椒ㄖ苽涔?碳復(fù)合負(fù)極材料，研究中采用掃描電鏡、紅外光譜和X-射線衍射對復(fù)合材料結(jié)構(gòu)進(jìn)行表征，并將其作為鋰離子電池負(fù)極材料探討硅/苯胺質(zhì)量比和負(fù)電極片制備工藝對其電化學(xué)性能的影響。研究表明：納米硅表面成功包覆了聚苯胺，且在高溫碳化過程中納米硅與碳之間沒有生成電化學(xué)惰性的碳化硅；復(fù)合負(fù)極材料制備過程中硅/苯胺質(zhì)量比為1:2，負(fù)電極片制備過程中復(fù)合負(fù)極材料/導(dǎo)電劑（Super p）/粘結(jié)劑（羧甲基纖維素鈉，CMC）的比例為85:5:10且采用pH=3的檸檬酸/氫氧化鉀緩沖液作為調(diào)漿溶劑時，所制備復(fù)合負(fù)極材料表現(xiàn)出高的比容量和良好的循環(huán)性能，經(jīng)20次循環(huán)后可逆容量仍為1013mAh/g。 （2）以納米硅和馬鈴薯淀粉為原料，通過高溫?zé)峤夂颓蚰刹椒ㄖ苽涔?碳復(fù)合負(fù)極材料，并將其作為鋰離子電池負(fù)極材料探討制備過程中球磨時間、硅石墨比例、調(diào)漿液pH值及粘結(jié)劑等因素對復(fù)合材料電化學(xué)性能的影響機(jī)制。結(jié)果表明：硅/石墨比為4:8，球磨時間為10小時，復(fù)合材料：導(dǎo)電石墨：CMC=85:5:10，pH=3的檸檬酸/氫氧化鉀緩沖液作為調(diào)漿溶劑時，復(fù)合材料的首次充放電比容量分別是1347mAh/g、934mAh/g，20次循環(huán)后充放電比容量仍高達(dá)1034.08mAh/g、985.34mAh/g，該復(fù)合材料顯示出良好的電化學(xué)性能。這是由于淀粉基炭包覆能夠有效地緩解由于硅在充電過程中體積膨脹而引起的電極粉化和剝落問題，另一方面復(fù)合材料中裸露的Si顆粒表面形成的羥基與CMC中之間形成了酯鍵，，這使電極片在充放電過程中保持了很好的完整性。
[Abstract]:Silicon is expected to be one of the candidate materials for graphite anode because of its high theoretical capacity of 4200mAh/ g) and abundant resources. However, the low conductivity, serious volume effect and poor cycle stability of silicon negative materials seriously restrict its commercial application. Carbon material is a mixed conductor of ions and electrons. It has little change in volume during charge and discharge, and has good ductility and elasticity, so it can be used as a "buffer matrix" for silicon anode materials. In addition, the lithium intercalation potential of the two materials is similar. Therefore, it is expected that a new type of lithium ion battery material with high capacity and good cycling performance can be prepared by combining the advantages of the two. In this study, aniline and starch were used as carbon source, nano-silicon as silicon source, and silicon / carbon composite anode materials were prepared by different preparation methods. Silicon / carbon composite anode materials were prepared by emulsion polymerization and high temperature pyrolysis from nano-silicon and aniline. The structure of the composite was characterized by scanning electron microscopy, infrared spectroscopy and X-ray diffraction. The effect of the mass ratio of silicon to aniline and the preparation process of negative electrode on the electrochemical performance of lithium ion battery was studied. The results showed that Polyaniline was successfully coated on the surface of nano-silicon and no electrochemical inert silicon carbide was formed between nano-silicon and carbon during high temperature carbonization. The mass ratio of silicon to aniline is 1: 2 in the preparation of composite negative electrode material. The ratio of composite anode material / conductive agent / binder is 85:5:10 and the citric acid / hydrogen oxidation of pH=3 is used in the preparation of negative electrode sheet. When potassium buffer is used as sizing solvent, The composite anode material showed high specific capacity and good cycling performance. After 20 cycles, the reversible capacity was still 1013mAh/ g. Using nano-silicon and potato starch as raw materials, silicon / carbon composite anode materials were prepared by high-temperature pyrolysis and ball milling, and used as anode materials for lithium ion batteries to discuss the milling time and the ratio of silicon to graphite. The influence of pH value of sizing fluid and binder on the electrochemical properties of composites. The results show that the ratio of silicon to graphite is 4: 8, and the milling time is 10 hours. When the conductive graphite: CMC: 85: 5: 5: 10 pH 3 buffer solution is used as the sizing solvent, The first charge-discharge capacity of the composite is 1347 mg / g 934 mg / g respectively. The charge-discharge capacity is still up to 1034.08 mg / g 985.34 mg / g after 20 cycles. The composite shows good electrochemical properties. This is due to the fact that the starch based carbon coating can effectively alleviate the problem of electrode pulverization and exfoliation caused by the volume expansion of silicon during the charging process. On the other hand, the hydroxyl groups formed on the surface of exposed Si particles in the composite materials form ester bonds between the hydroxyl groups formed on the surface of the bare Si particles and the CMC particles. This makes the electrode sheet in charge and discharge process to maintain a good integrity.
【學(xué)位授予單位】：重慶大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：O613.72;TM912

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