請用此 Handle URI 來引用此文件:
http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/71745
標題: | 奈米錳化物尖晶石材料於能源儲存裝置之製備 Synthesis of Advanced Manganese Spinel Nanostructures for Energy Storage |
作者: | Mozaffar Abdollahifar 艾莫法 |
指導教授: | 吳乃立(Nae-Lih Wu) |
關鍵字: | 錳尖晶石氧化物,碳包覆ZnMn2O4,四方晶系LiMn2O4,Mn3O4奈米粒子,超級電容器,儲能裝置,同步輻射X射線分析,新合成方法., Manganese Spinel Oxides,Carbon-Coated ZnMn2O4,Tetragonal LiMn2O4,Mn3O4 Nanoparticles,Supercapacitor,Energy Storage,Synchrotron X-Ray Analyses,Novel Synthesis Methods., |
出版年 : | 2018 |
學位: | 博士 |
摘要: | 本論文以合成先進的錳尖晶石氧化物,如ZnMn2O4,Mn3O4和四方晶系LiMn2O4,作為儲能應用,由於其具有比電容高,成本低,豐富,環保等優勢。在本論文的第一部分,獨特碳包覆的ZnMn2O4 (CZMO)奈米微晶首次通過使用聚乙二醇作為多功能微結構導向劑的新型溶液燃燒方法成功合成。且其在中性水系電解質中顯示出高性能偽電容行為。通過一鍋法合成工藝,並控制燃燒溶液中聚合物的分子量和數量,形成具有中孔結構和保形碳包覆的高度結晶的C@ZMO,其具有顯著更高,超過5倍的比表面積。在Na2SO4(aq)電解質中,C@ZMO超級電容器電極表現出理想的電容行為,其特定電容高達150 F g-1,並且循環穩定性表明在10,000次循環後沒有電容衰減,並且> 99%庫侖效率。該研究不僅展示了一種新的強大的合成路線,其能生產用於儲能應用的導電介孔結晶氧化物基奈米材料,而且還揭示了一類新的高性能偽電容材料,用於中性水溶液電解質。在第二部分中,通過新型原位低溫離子交換法,由奈米晶ZnMn2O4的製備一種獨特的奈米結構四方LiMn2O4(TLMO),該電極在含Li離子的水系電解液中具有混合偽電容和電池行為。在高容量,長循環穩定性和抑制自放電的組合方面,偽電容和電池特性之間的互補作用使得TLMO表現優異,相對於僅具有任何一種電化學行為的材料,以及許多其他值得注意的偽電容材料。使用原位同步加速器X射線分析揭示離子交換過程和電荷存儲機制期間的相變機制。該研究可能在電荷存儲電極材料中開闢了一種新的設計理念。在第三部分中,我們通過簡單的化學方法在室溫下合成了具有高導電性的Mn3O4單奈米顆粒,並使用2-甲基咪唑作為弱沉澱劑來控制Mn3O4奈米顆粒。實驗結果表明,所涉及的反應物和溶劑種類的初始摩爾濃度對於製備目標產物是至關重要的。具有單個奈米顆粒的適當導電碳可有助於使活性材料在電極上完美分散。我們引入這種技術,製備高速電極作為理想的超級電容器,其具有超長的循環壽命穩定性,並有高速和慢速電流循環的靈活性。該電極具有增強的倍率性能(在60 A g-1下保留容量為66%),具有優異的電化學穩定性,在100,000次重複快速(100 A g-1,高電流性能)和慢速(1 A g-1後保持100%,用於高容量存儲)充電/放電循環。優異的電化學性能可歸因於導電碳和電極中的Mn3O4奈米顆粒之間的協同效應。因此,這是一種製備獨特的Mn3O4奈米粒子的方法,適用於高速率和超長循環壽命的超級電容器,它可以非常有利於真正的儲能應用。 In this dissertation, the concentrate will be on the synthesis of advance manganese spinel oxides such as ZnMn2O4, Mn3O4 and tetragonal LiMn2O4 electrodes for energy storage applications, due to their advantages, such as high specific capacitance, low-cost, abundance and environmentally friendly nature. In the first part of this dissertation, a unique carbon-coated ZnMn2O4 (C@ZMO) nanocrystallites showing high-performance pseudocapacitor behaviours in neutral aqueous electrolyte are for the first time successfully synthesised via a novel solution combustion process using polyethylene glycol as a multifunctional microstructure-directing agent. Controlling the molecular weight and amount of the polymer in the combustion solution enables the formation of highly-crystalline C@ZMO having substantially higher, by more than 5 folds, specific surface areas with mesoporous structures and conformal carbon coating via the one-pot synthesis process. The resulting C@ZMO supercapacitor electrodes in Na2SO4(aq) electrolyte exhibit ideal capacitive behaviours with specific capacitances up to 150 F g−1 and cycle stability showing no capacitance fade after 10,000 cycles, and >99% Coulombic efficiency. This study not only illustrates a new powerful synthesis route capable of producing conductive mesoporous crystalline oxide-based nanomaterials for energy storage applications but also reveals a new class of high-performance pseudocapacitive materials for neutral aqueous electrolytes. In the second part, a unique nanostructured tetragonal LiMn2O4 (TLMO) electrode exhibiting mixed pseudocapacitor and battery behaviours in Li ion-containing aqueous electrolytes is derived via a novel in-situ low-temperature ion-exchange method from nanocrystalline ZnMn2O4. The complementary actions between the pseudocapacitance and battery properties enable TLMO to substantially outperform, in terms of the combination of high capacity, long cycle stability and suppressed self-discharge, its counterparts having only either one of the electrochemical behaviours, along with many other notable pseudocapacitive materials. The phase transformation mechanism during the ion-exchange process and charge-storage mechanisms are revealed using operando/in situ synchrotron X-ray analyses. This study may open up a new design concept in charge-storage electrode materials. In the third, part we have synthesized Mn3O4 single nanoparticles with high conductivity via a simple chemical method at room temperature, using 2-methyleimidazole as weak precipitation agent for controlling of Mn3O4 nanoparticles. The experimental results reveal that the initial molar concentration of reactants and solvent species involved are crucial for preparing the target product. A proper conductive carbon with single nanoparticles can be help to make a prefect dispersion of active materials on the electrode. We introduce this technique to make a high rate electrode as ideal supercapacitor with ultra-long cycle life stability, and flexible with high and slow current rate cycling. This electrode exhibited enhanced rate capability (66 % retained capacity at 60 A g-1), and excellent electrochemical stability with 100 % retention after 100,000 repetitive fast- (20 A g-1, for high current performance) and slow- (1 A g-1, for high capacity storage) charging/discharging cycles. The excellent electrochemical performance can be ascribed to the synergistic effect between the conductive carbon and the Mn3O4 nanoparticles in the electrode. Therefore, this method is a unique Mn3O4 nanoparticles production for high rate and ultra-long cycle life supercapacitors, which can be a very favourable for real energy storage applications. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/71745 |
DOI: | 10.6342/NTU201804373 |
全文授權: | 有償授權 |
顯示於系所單位: | 化學工程學系 |
文件中的檔案:
檔案 | 大小 | 格式 | |
---|---|---|---|
ntu-107-1.pdf 目前未授權公開取用 | 10.46 MB | Adobe PDF |
系統中的文件,除了特別指名其著作權條款之外,均受到著作權保護,並且保留所有的權利。