本文選題：鋰硫電池 + CNT　； 參考：《鄭州大學》2017年碩士論文

【摘要】：鋰硫(Li-S)電池具有超高的理論能量密度(2600 Wh/kg),且電極材料硫儲量豐富、價格便宜,已成為當前二次電池領域極具競爭力的研究體系之一。但在電極反應過程中,由于硫材料導電性差、充放電中間產物“飛梭效應”等原因,實際制備的電池往往面臨容量衰減快、倍率性不強等問題,阻礙了Li-S電池的進一步應用與推廣。從金屬氧化物與多硫化物的界面作用出發(fā),本研究提出以金屬氧化物修飾不同碳-硫復合電極材料,探索納米粒子吸附、殼層包覆等微結構對Li-S電池電化學性能的影響。本文主要研究內容如下:(一)納米銻摻雜二氧化錫(Sb:SnO_2,ATO)修飾碳納米管-硫復合電極材料的制備及其電化學性質的研究。以商用CNT為導電網絡骨架,通過機械混合法將其與導電ATO納米顆�；旌�,并采用熔融法實現單質硫均勻包覆。研究表明CNT導電網絡提升了電極導電性及硫負載量,而ATO顆粒則通過吸附作用抑制了“飛梭效應”。通過優(yōu)化可知當ATO摻入量為2%時,電池容量衰退速率最低,其初始容量為982 mAh/g,200次循環(huán)后,容量剩余66.5%,相對于不加ATO的樣品容量提高了43.8%。(二)MnO_2包覆碳化聚乙烯亞胺-硫復合電極材料的濕化學原位氧化法制備及其電化學性能研究。以線性聚乙烯亞胺(LPEI)為模板制備了具有三維貫通結構的多孔碳材料并將其負載單質硫,以KMnO4溶液為氧化劑和錳源,通過原位氧化還原反應在碳-硫復合結構表面生成一層片狀MnO_2的包覆層。研究結果表明,表面MnO_2包覆層的限域效應可顯著抑制多硫化鋰的擴散,使得組裝電池的庫倫效率明顯提升。適量氧化的樣品在200次循環(huán)后容量剩余達485mAh/g,更重要的是其庫倫效率保持在96%以上,而未氧化的樣品200次循環(huán)后庫倫效率僅為84%。
[Abstract]:Li-Sc battery has a high theoretical energy density of 2600 / kg 路kg ~ (-1), and its electrode material is rich in sulfur reserves and cheap in price, so it has become one of the most competitive research systems in the field of secondary battery. However, during the electrode reaction, due to the poor conductivity of sulfur materials and the "shuttle effect" of the intermediate product of charge and discharge, the batteries prepared in practice often face the problems of fast capacity attenuation and low rate, etc. It hinders the further application and popularization of Li-S battery. Based on the interfacial interaction between metal oxides and polysulfides, the effects of metal oxides on the electrochemical properties of Li-S batteries were investigated by modifying different carbon-sulfur composite electrode materials with metal oxides to explore the effects of nano-particle adsorption and shell coating on the electrochemical performance of Li-S batteries. The main contents of this paper are as follows: 1. The preparation and electrochemical properties of carbon nanotube-sulfur composite electrode modified by SB: SnO2ATO) doped with SB: SnO2ATO. Commercial CNT was used as the framework of conductive network, and it was mixed with conductive ATO nanoparticles by mechanical mixing method, and the homogeneous coating of elemental sulfur was realized by melting method. The results show that CNT network enhances the electrode conductivity and sulfur load, while ATO particles inhibit the "shuttle effect" by adsorption. The results show that when the ATO incorporation is 2, the cell capacity decline rate is the lowest, its initial capacity is 982 mg / g ~ (-1). After 200 cycles, the residual capacity is 66.5%, which is 43.8% higher than that of the sample without ATO. Preparation and Electrochemical Properties of Carbide Poly (ethyleneimide-Sulphur) Composite electrode Materials coated with MNO _ 2 by in situ Wet Chemical Oxidation method. Porous carbon materials with three dimensional penetrating structure were prepared using linear polyethylene imide (LPEI) as template and supported on elemental sulfur. KMnO4 solution was used as oxidant and manganese source. A lamellar MNO _ 2 coating was formed on the surface of carbon-sulfur composite structure by in-situ redox reaction. The results show that the limiter effect of MnO2 coating can significantly inhibit the diffusion of lithium polysulfide and increase the Coulomb efficiency of the assembled battery. After 200 cycles, the residual capacity of oxidized samples is 485 mg / g. More importantly, the Coulomb efficiency of oxidized samples remains above 96%, while that of unoxidized samples after 200 cycles is only 84%.
【學位授予單位】：鄭州大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TB33;TM912

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本文編號：1983787