高孔體積五氧化二釩氣凝膠之製備及其在鋰二次電池陰極材料之應用

Preparation of High Pore Volume Vanadium Pentoxide Aerogel for Electrode of Rechargeable Lithium Battery

莊博鈞(Po-Chun Chuang)

指導教授 ： 陳玉惠

中原大學/理學院/奈米科技碩士學位學程/碩士(2009年)

https://doi.org/10.6840/cycu200900862

摘要

本研究係以溶膠-凝膠法(Sol-gel method)，並以離子熔液作為模板，成功製備出高孔體積之五氧化二釩氣凝膠。並將五氧化二釩氣凝膠與市售結晶型五氧化二釩混合，製備出五氧化二釩複合電極，應用於鋰二次電池中，同時探討添加高孔體積之五氧化二釩氣凝膠對於電化學性質及電池效能之影響。
由材料分析及鑑定結果顯示，所製備之五氧化二釩氣凝膠為具中孔洞之非結晶性多孔材料，且同時具有高比表面積及高孔體積。藉由改變溶劑及前驅物可製備出不同孔體積及比表面積之五氧化二釩氣凝膠。其中以Vanadium oxytriisopropoxide為前驅物，異丙醇為溶劑，並以離子熔液為模板可製備出孔體積最高之五氧化二釩氣凝膠Pvip。
循環伏安(CV)測試結果顯示，所製備之五氧化二釩複合電極，其CV比電容量會隨所加入之五氧化二釩氣凝膠的孔體積升高而增加。CV之循環穩定性，因含10 wt%五氧化二釩氣凝膠Pvip後而有提升，於第100循環時循環能力由66 %提升至97 %。
定電流充放電測試顯示，含10 wt%五氧化二釩氣凝膠Pvip後，比表面積及孔體積皆有所提升，對於電解液接觸面積變大及鋰離子嵌入位置變多，使其於快速充放電(1C)下，可減少40 %之不可逆電容量產生，同時電容量明顯提升約150 mAh/g，為市售五氧化二釩製備之電極E-Cm電容量的2.7倍，並且於十次放電後電容量依然可維持於225 mAh/g。

關鍵字

鋰電池 ； 氣凝膠 ； 五氧化二釩

並列摘要

In this study, the high pore volume vanadium pentoxide aerogel has been successfully prepared by the sol-gel polymerization with an ionic liquid as the template. Furthermore, the vanadium pentoxide composite electrode was prepared by mixing the as-prepared vanadium pentoxide aerogel with the commercial crystalline vanadium pentoxide for use in the rechargeable lithium battery. In addition, the effects of the added high pore volume vanadium pentoxide aerogel on the electrochemical properties and performance of the rechargeable lithium battery are also investigated.
The result shows that the as-prepared vanadium pentoxide aerogel is a non-crystalline high porosity mesoporous material with high surface area and high pore volume. It is found that the surface area and pore volume of the vanadium pentoxide aerogel are varied by changing the precursor and solvent used in preparation. The highest pore volume vanadium pentoxide aerogel was prepared by using vanadium oxytriisopropoxide as the precursor, isopropanol as the solvent and the ionic liquid as the template.
The result of cyclic voltammetry (CV) test shows that the as-prepared vanadium pentoxide composite electrode with the high pore volume vanadium pentoxide aerogel provides the higher capacitance. Besides, the composite electrode (E-Pvip) with 10wt% of the vanadium pentoxide aerogel, Pvip, exhibits better cycle stability of its CV. Comparing with that for E-Cm, the electrode made with the plain commercial vanadium pentoxide, the 100th cyclic ability of CV for E-Pvip improves from 66% to 97%.
The results of the charge-discharge test with the fast charge-discharge rate (1C) shows that the as- prepared vanadium pentoxide composite electrode (E-Pvip) reduces 40% of the irreversible capacity and increases the capacity for about 150 mAh/g. The capacity of E-pvip was 2.7 times higher than that of E-Cm. In addition, after ten times discharges, the capacity of E-Pvip still remains 225 mAh/g. This is ascribed to the higher surface area and pore volume of Pvip, that provies more contact surface area with the electrolyte and more sites for intercalation with more of the lithium ions.

並列關鍵字

aerogel ； vanadium pentoxide ； lithium battery

參考文獻

[9] B. Scrosati (1992). J. Electrochem. Soc., 139, 2776-2780.

[18] T. Ohzuku and A. Ueda (1994). J. Electrochem. Soc., 141, 2972-2977.

[19] J. N. Reimers and J. R. Dahn (1992). J. Electrochem. Soc., 139, 2091-2097.

[20] C. Delmas (1980). Mater. Sci. Eng., B3, 97-101.

[21] L. P. L. M. Rabou and A. Roskam (1995). J. Power Sources, 54, 316-318.