富鋰相層狀結構正極材料之製備與特性研究

Preparation and characterization of Lithium Excess Layer-structured Cathode Materials

蔡宏暉(Hung-huei Tsai)

指導教授 ： 吳溪煌

大同大學/工程學院/材料工程學系所/碩士(2012年)

摘要

以Pechini法合成複合相層狀結構之xLi2MnO3‧(1-x)LiMn0.9Cr0.1O2 (0.1 ≤ x ≤ 1 ) 鋰離子二次電池正極材料粉末。以 ICP-OES、XRD、EA、SEM分析合成粉末之組成、結晶結構、碳含量及表面形態，以循環充放電測試分析不同組成之正極材料粉末之電化學特性。由XRD分析結果可得知，其生成粉末主要為 o-LiMnO2、m-LiMnO2、r-LiMnO2和m-Li2MnO3相的結構。以30、300、和1500 mA/g之電流密度下進行循環充放電，以xLi2MnO3‧(1-x)LiMn0.9Cr0.1O2 (x = 0.5)為正極的鈕釦型電池之可逆比電容量可分別為 201、140、和115 mAh/g。經以氧化鋁和氧化鋅進行表面改質以改善此種正極材料的結構、可逆比電容量及循環充放電穩定性。發現以氧化鋅表面改質的xLi2MnO3‧(1-x)LiMn0.9Cr0.1O2 (x = 0.5)材料在30、300、和1500 mA/g循環充放電電流下之可逆比電容量分別為 280、200、和150 mAh/g。此外，並與MCMB負極組裝成全電池進行相關該電極材料的電化學特性探討與評估。

關鍵字

正極材料 ； 複合相層狀結構 ； 鋰離子電池

並列摘要

Layered xLi2MnO3‧(1-x)LiMn0.9Cr0.1O2 (0.2 ≤ x ≤ 1) cathode materials are synthesized by Pechini’s method. The composition, crystal structure, carbon contents, and morphologies of as-prepared powders are investigated using ICP-OES, XRD, EA, and SEM. and electrochemical testing, respectively. The XRD results show that the as-prepared powders are mainly composed of o-LiMnO2, m-LiMnO2, r-LiMnO2, and m-Li2MnO3 phases. The reversible capacities obtained from capacity retention study are 234, 151, and 116 mAh/g at the current densities of 30, 300, and 1500 mA/g, respectively. In order to improve the cycling performance of the materials, the pristine powders are coated with aluminium or zinc oxides on their surface to stabilize their structure. The zinc oxide coated samples manifest reversible capacities of 280, 200, and 150 mAh/g at the current densities of 30, 300, and 1500 mA/g, respectively. In addition, full cell are assembled to study and evaluate the electrochemical properties of this layered compounds.

並列關鍵字

Lithium ion batteries ； composite layered structure ； cathode materials

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