發(fā)布時間：2018-02-10 04:11

  本文關(guān)鍵詞： 二維納米碳 分級結(jié)構(gòu) 氮摻雜 多孔結(jié)構(gòu) 儲鋰性能　出處：《中國科學(xué)技術(shù)大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：二維納米碳材料在新一代能量存儲與轉(zhuǎn)換體系中被廣泛地應(yīng)用和研究。當(dāng)被用作鋰離子電池負極材料時,其超高的比表面積可以提供豐富的電化學(xué)活性位點,從而保證了材料的高比容量。其二維納米結(jié)構(gòu)可以縮短Li+離子的擴散路徑、提升材料的倍率性能。其優(yōu)異的機械性能保證電極具有良好的結(jié)構(gòu)穩(wěn)定性,從而使材料獲得優(yōu)異的循環(huán)性能。然而由于范德瓦爾斯力的存在,二維納米碳材料通常會面臨嚴重的團聚和堆疊效應(yīng),這造成了有效比表面積的損失,阻礙了 Li+離子的擴散。構(gòu)建二維分級結(jié)構(gòu)可以有效地緩解這種團聚與堆疊,促進二維納米碳材料高比表面積的充分利用。此外,優(yōu)化孔徑分布、雜元素功能化均對提升二維納米碳材料的儲鋰性能有重要的意義。傳統(tǒng)制備分級納米碳材料的方法耗時耗能、價格昂貴且產(chǎn)率低,遠不能滿足需求。因此,用環(huán)境友好型方法制備二維分級納米碳材料是一個有前景的研究方向。本文中的研究內(nèi)容主要集中于以下幾點:(1)以鎂鋁雙金屬氫氧化物為模板,吸收工業(yè)污水中的常見有機染料橙黃Ⅱ作為碳源,制備了一種二維分級納米碳材料(2D-HCA),并用一系列的表征手段研究了這種分級碳材料的微觀結(jié)構(gòu)、探究了它的制備機理。實驗結(jié)果表明,2D-HCA由二維納米亞單元組成;同時,這種碳材料具有分級孔結(jié)構(gòu)和N、S雜元素共摻雜的特性。(2)基于2D-HCA的制備方法,進一步以三聚氰胺為氮源,用"一步摻雜法"成功制備了富氮二維納米碳(N-2D-HCA),并表征了 N-2D-HCA的結(jié)構(gòu),分析了 N元素的含量和種類。實驗結(jié)果表明,N-2D-HCA也具有由二維納米亞單元組成的分級結(jié)構(gòu);N-2D-HCA含N量為15.5%,其中電化學(xué)活性高的吡啶氮和吡咯氮占所有N原子的84%。(3)測試了兩種分級納米碳的儲鋰性能,包括循環(huán)伏安曲線、循環(huán)性能、倍率性能等。電化學(xué)數(shù)據(jù)表明,2D-HCA表現(xiàn)出了極高的儲鋰比容量、N-2D-HCA表現(xiàn)出了優(yōu)異的循環(huán)穩(wěn)定性。本文的實驗結(jié)果表明,通過構(gòu)建二維分級結(jié)構(gòu)的納米碳材料,能夠有效地緩解納米碳單元片層間的團聚與堆疊,有效提高二維納米碳材料表面積利用率,實現(xiàn)其優(yōu)異的儲鋰性能。本論文以有機染料橙黃Ⅱ為碳源,制備出具有優(yōu)異儲鋰性能的二維分級結(jié)構(gòu)納米碳材料,實現(xiàn)了污染物的綠色利用。
[Abstract]:Two-dimensional nano-carbon materials have been widely used and studied in the new generation of energy storage and conversion systems. When used as anode materials for lithium ion batteries, their ultra-high specific surface areas can provide abundant electrochemical active sites. Thus, the high specific capacity of the material is ensured. The two-dimensional nanostructure can shorten the diffusion path of Li ion and improve the performance of the material. Its excellent mechanical properties ensure the electrode has good structural stability. However, due to the existence of van der Waals force, two-dimensional nano-carbon materials usually face serious agglomeration and stacking effect, which results in the loss of effective specific surface area. The structure of two-dimensional hierarchical structure can effectively alleviate the agglomeration and stacking, and promote the full utilization of high specific surface area of two-dimensional carbon nanomaterials. In addition, the pore size distribution can be optimized. The functionalization of heterogenous elements is of great significance in improving the lithium-storage properties of two-dimensional nano-carbon materials. Traditional methods for preparing graded nano-carbon materials are time-consuming, energy consuming, expensive and low yield, and can not meet the demand. It is a promising research direction to prepare two-dimensional graded nano-carbon materials by environment-friendly method. The research contents in this paper are mainly focused on the following points: 1) Mg-Al bimetallic hydroxides are used as templates. A 2-D graded nano-carbon material was prepared by absorbing orange 鈪，

本文編號：1499626