查詢結果分析
來源資料
頁籤選單縮合
題 名 | 低溫固化樹脂石墨改質作為鋰電池負極材料研究=Resin Solidification at Low Temperature of Graphite Modification as Anode Materials for Lithium Ion Battery |
---|---|
作 者 | 吳玉祥; 謝宗坤; | 書刊名 | 中華科技大學學報 |
卷 期 | 46 2011.01[民100.01] |
頁 次 | 頁15-32 |
分類號 | 468.1 |
關鍵詞 | 鋰離子電池; 天然石墨; 催化劑; 碳披覆; 表面改質; Lithium-ion batteries; Natural graphite; Catalyst; Carbon coating; Surface modification; |
語 文 | 中文(Chinese) |
中文摘要 | 本研究以表面改質之碳披覆方法,於球形天然石墨表面披覆一層非晶質碳膜來穩定石墨的層間結構,改善鋰離子電池的負極材料表面結構與電化學特性,並降低充放電中第一次不可逆性與電容量衰退。實驗以呋喃樹脂作為碳披覆材料,其含量分別為15 wt.%、20 wt.%、25 wt.%,乙二醇作為溶劑,以去離子水來分散石墨粉體,並藉由催化劑的影響使其能在50℃溫度下固化,再經由1100℃ 3小時熱處理形成非晶質碳膜。實驗分析以掃描式電子顯微鏡(SEM)觀察表面形態,顯示改質前後的表面型態由粗糙變為較平滑,且隨著混合液比例增加,能使凝聚現象降低;藉由拉曼(Raman)光譜分析石墨表面性質,並證實改質後R value有明顯提高;以X光繞射分析(XRD)石墨特性,得知層間距離d(002)的增加與石墨化度降低,以及菱面晶比例增加,顯示非晶質碳材已均勻披覆在石墨表面上,改變石墨的表面結晶特性;從充放電循環分析可以證實經由改質之石墨,其第10次放電電容量從原始石墨的224 mAh/g提高到20 wt.%的284 mAh/g,且使庫倫效率提高,充放電循環更為穩定。樹脂的含量在20 wt.%時,其第一次不可逆性在10%以下,且庫倫效率有90%以上,較符合鋰離子電池負極材料規格。因此呋喃樹脂以低溫固化方式形成之非晶質碳膜,可有效改善天然石墨的電容量衰退與提高庫倫效率。 |
英文摘要 | A layer of amorphous carbon is coated over the surface of spherical natural graphite through the method of surface-modified carbon coating, to stabilize the surface structure and electrochemical properties of anode materials in Li-ion battery, and to reduce the first irreversibility and capacity fading during charging and discharging. Furan resin is used as carbon coated materials with 15, 20, and 25 wt.%. With ethylene glycol as a solvent, the resin is dissolved in deionized water to produce. Catalyst is then added to enable curing at a temperature of below 50℃ before they are put through a 1100℃, 3-hour heat treatment to form amorphous carbon film. In the experimental analysis using scanning electron microscopy (SEM), it reveals that before and after modification, the surface morphology changed from rough into smooth while the sign of condensation will reduce with an increase in mixture ratio. Raman spectra analysis of the graphite surface confirmed that R value increases significantly after modification. The analysis of graphite characteristics using X-ray diffraction (XRD) shows that an increase in the distance d(002) between layers is related to a decrease in graphitization. An increase in the percentage of rhombohedral crystal suggests that amorphous carbon material has been evenly coated on the graphite surface. The charging and discharging cycle test can confirm that the capacity of the modified graphite on the 10th discharge has increased from 224 mAh/g of the original graphite to 284 mAh/g of 20 wt.% resin coating, and enhance columbic efficiency. It also makes the charging and discharging cycle more stable. The 20 wt.% resin content shows better quality in the 1st irreversibility and columbic efficiency. Therefore, amorphous carbon film produced from furan resin in low temperature curing can effectively improve capacity fading and columbic efficiency of natural graphite. |
本系統中英文摘要資訊取自各篇刊載內容。