複合型鋰鎳鈷錳正極材料電化學性質研究

On the Study of Electrochemical Properties for Composite LiNi1-x-yCoxMnyO2 Cathode Material

呂杰璉(Chieh-Lien Lu)

指導教授 ： 施漢章

國立清華大學/工學院/材料科學工程學系/碩士(2007年)

https://doi.org/10.6843/NTHU.2007.00362

摘要

本實驗在探討使用鋰鈷鎳三種元素合成的正極材料LiNi0.8Co0.15Mn0.05O2的電化學性質研究。主要分為兩個階段，第一階段為針對各種合成LiNi0.8Co0.15Mn0.05O2¬的變數做分析，分別改變燒結溫度及燒結時間來燒結材料，燒結出來的材料將利用Ｘ光繞射分析儀及掃瞄式電子顯微鏡分析其表面之形貌並比較之。並且將各個條件下得到的LiNi0.8Co0.15Mn0.05O2均做成電極板並組成電池。例用C-Rate、Cycle life及CV等電性測試來比較哪個燒結條件所得到的電性最好。

後半部針對較佳且符合成本的燒結條件為基礎，針對其電性不足之處(高電壓下循環穩定性不佳)及鋰鈷鎳錳材料的高放熱性進行改進；本實驗將用不同比例 (2% 和3%)的Al2O3、Mg2O3利用固態燒結法及ZrO2用溶液分散法做材料的表面修飾。實驗結果發現電容量沒有因為氧化物的表面修飾而降低太多，且電池之循環穩定性也沒有比較差；使用2wt%的鋁離子做表面修飾的材料在4.5V下的循環穩定性比未做表面修飾的試片好很多，是很有機會發展的材料之一。

關鍵字

鋰電池 ； 鋰離子二次電池 ； 鎳酸鋰 ； 鎳鈷錳

並列摘要

This research is about LiNi0.8Co0.15Mn0.05O2 cathode material of lithium ion secondary batteries made by nickel, cobalt, and manganese. First we changed the conditions of calcination such as temperature (750℃, 800℃ and 850℃) and calcination time (8hr and 12hr). X-ray diffractometer (XRD) and scanning electron microscope (SEM) can help us to analyze and compare morphologies of LiNi0.8Co0.15Mn0.05O2. Comparison of C-Rate, cycle life, cyclic voltammetry (CV) test of the final coin cells can let us know which conditions are the best for LiNi0.8Co0.15Mn0.05O2.

Surface modifications were done in the second half of this research. Base on the applicable synthesis conditions, different ratios of Al2O3(2%, 3%), MgO(2%, 3%) and ZrO2(1%, 2%) are used to coat on LiNi0.8Co0.15Mn0.05O2. From the results we found that capacities of the batteries decrease little and cycle life performances were similar with the bare LiNi0.8Co0.15Mn0.05O2. 2wt% Al2O3 coated LiNi0.8Co0.15Mn0.05O2 shows the best cycle ability when the voltage increases to 4.5V. It is the potential material.

並列關鍵字

Li-ion battery ； lithium ion secondary battery ； LiNi0.8Co0.15Mn0.05O2

參考文獻

1.H. P. Hsu, J. M. Chen, T. S. Shih, Y. W. Lin, and C. Y. Yao, “鋰離子電池材料技術” 工業材料, 126 (1997)104

3.M. S. Whittingham, R. Chen, T. Chirayil and P. Zavalij, “The intercalation and hydrothermal chemistry of solid electrodes” Solid State Ionics, 94(1997) 227

4.D. Rahner, S. Machill, H. Schlorb, K. Siury, M. Klob, and W. Plieth, “Intercalation materials for lithium rechargeable batteries” Solid State Ionics, 86-88(1996)891

5.T. Nohma, H. Kurokawa, M. Uehara, M. Takahashi, K. Nashio and T. Saito, “Electrochemical characteristics of LiNiO2 and LiCoO2 as a positive material for lithium secondary batteries“ J. Power Sources 54 (1995) 522.

6.K. Mizushima, P. C. Jones, P. J. Wiseman and J. B. Goodenough, “ LixNiO2 : A new cathode material for batteries of high energy density” Mater. Res. Bull. 15(1980)783-789