透過您的圖書館登入
IP:18.206.160.129
  • 學位論文

非晶鍺與多晶鍺微米粒子的合成與它們於鋰電池負極上的比較

Synthesis of Micrometer-sized Amorphous and Polycrystalline Germanium Particles and Their Performance Comparison as Lithium-ion Battery Anodes

指導教授 : 段興宇

摘要


本篇研究使用超臨界熱裂解法(Supercritical thermal decomposition method),透過調整不同的反應溫度和界面活性劑,合成出非晶和多晶鍺微米粒子並加以比較兩種鍺微米粒子於鋰電池上的表現。第一步藉由掃描式電子顯微鏡、穿透式電子顯微鏡、X 光繞射儀及高解析TEM 分析鍺微米粒子,判斷微米粒子是非晶或多晶,從而組成鋰電池再以電化學儀器測試,其實驗內容共使用兩種方法:第一種為恆電流法;第二種為循環伏安法。 在室溫下,以恆電流法進行0.1C(=139mAg-1)及1C(=1384mAg-1)的充放電, 用以比較經多次充放電循環後,兩者的電容量穩定性、充放電循環的微分電容圖。 接著,利用不同充放電速率進行測試,分析不同速率的電容量以比較非晶和多晶 鍺微米粒子的不同處。最後則利用循環伏安法比較兩者在前幾個循環的電化學反 應電位不同處。實驗結果顯示於充放電速率於1C 充放100 次後,多晶鍺微米粒 子的電容穩定性(96%)優於非晶鍺微米粒子(55%)。此外,多晶鍺微米粒子在第一 次循環充電的微分電容圖比非晶鍺於0.35V 附近多一個反應訊號此為結晶鍺轉 非晶鍺的特徵。從循環伏安法得知,兩者間的不同在於多晶鍺第一個循環的還原 電位多了一個0.3V 的反應訊號外,而非晶鍺在氧化電位比多了0.36V 的反應訊 號。

關鍵字

鋰電池 合成 負極 比較

並列摘要


The purpose of this study is to synthesize micrometer-sized particles of amorphous and polycrystalline germanium by supercritical thermal decomposition’s method and ultimately draw a comparison between the behavior of these two particles in lithium batteries. To investigate the phase and size of germanium particles and further develop them in lithium batteries, an analysis of germanium particles is conducted with scanning electron microscope, transmission electron microscope,X-ray diffraction and HR-TEM. Moreover, two electrochemical methods are employed so as to compare and contrast the pattern of these two micrometer-sized particles of amorphous and polycrystalline germanium. One is galvanostatic method.The other is cyclic voltammetry (CV).On exploring differences in stability of capacity and differential capacity profiles between amorphous and polycrystalline germanium, a discharge-charge cycling is performed under the galvanostatic method at ambient temperature. In this method, the voltage ranges from 0.01V to 3V at 0.1C discharge -charge rate. Next, a cyclic voltammetry (CV) experiment in different potential is carried out for the analysis of multi-rate discharge-charge capacity between amorphous and polycrystalline germanium micrometer-sized particles. The experiment results indicate that polycrystalline germanium’s cyclic stability(96%) for high rate (1C) 100cycles is better than that of amorphous germanium(55%). In addition, from differential capacity and cyclic voltammetry profiles, we understand that there exist differences between amorphous and polycrystalline germanium in lithiated and de-lithiated potential.

並列關鍵字

Germanium Lithium-ion battery Synthesis Anode Comparison

參考文獻


1.Schalkwijk W. and Scrosati B., Advances in lithium ion batteries-introduction advances in lithium-ion batteries, W. Schalkwijk and B.Scrosati, Editors. 2002, Springer US. p. 1-5.
2.Marchioni F., et al., Protection of lithium metal surfaces using chlorosilanes. Langmuir, 2007. 23(23): p. 11597-11602.
3.Tarascon J.M. and Armand M., Issues and challenges facing rechargeable lithium batteries. Nature, 2001. 414(6861): p. 359-67.
4.Kalaiselvi N., et al., Synthesis of optimized LiNiO2 for lithium ion batteries. Ionics, 2003. 9(5): p. 382-387.
5.Kim D.K., et al., Spinel LiMn2O4 nanorods as lithium ion battery cathodes. Nano Lett., 2008. 8(11): p. 3948-3952.

延伸閱讀