消費性電子產品之微小化，對高能量密度鋰離子電池產生強烈之需求。從行動電話、數位相機至筆記型電腦等，國內每年對於鋰離子電池之需求量約兩億顆，市場產值超過十億美金。 LiCoO2 為目前鋰離子電池市售材料中使用最廣泛之陰極材料，然而其可逆電容量不高，且在充電截止電壓大於4.3 伏特時，金屬鋰會從LiCoO2 材料中析出，導致有安全上之疑慮，且當電池誤用時，金屬鋰會造成火險。LiNi0.8Co0.2O2 材料之可逆電容量較高，但亦有安全性問題，僅程度較小而已。在本計劃中，為達到縮短製程時間、減少合成費用，並製備高性能之LiNi1/3Co1/3Mn1/3O2 陰極材料，吾人分別以溶液燃燒法和微波處理法進行此材料之製程開發，經由改變各重要合成變因，尋找最佳製程條件。隨後，以機械式熱處理法，嘗試利用不同氧化物，將兩方法最佳製程的陰極材料進行塗佈改質，期能改善材料於高充電電壓下之循環穩定性，並提升其熱安定性與承受高速率充放電的總體能力。相較於傳統共沉澱合成法，吾人以溶液燃燒法和微波處理法，進行LiNi1/3Co1/3Mn1/3O2 之材料製備，兩方法不僅具備快速、方便與經濟的特點，溶液燃燒法與微波處理法更分別具有製程簡單與反應快速之絕對優勢。在未來如此分秒必爭的年代，吾人所開發之製備方式，不僅大幅縮減了製程時間與人物力生產投資成本，亦提高了能源材料於市場應用的絕對競爭力。溶液燃燒法和微波處理法，的確更適用於大量的工業量產上，亦可視為相當具潛力的陰極材料製備方法。 ; Miniaturization of consumer electronics has created a strong demand for high energy density systems of lithium-ion batteries (LIBs). From cellular phones and digital cameras to notebook PCs, the annual domestic demand for LIBs exceeds two hundred million cells, which translates into a multi-billion USD market. LiCoO2 is the most widely used commercial cathode material for LIBs. However, it suffers from severe limitations in cell capacity and safety due to overcharge problems, which occur when the cut-off charge potential exceeds 4.3 volts and metallic lithium can be electrodeposited from LiCoO2. The formation and presence of metallic lithium may create a fire hazard during extreme use. LiNi0.8Co0.2O2 with its higher capacity also has safety concerns, although to a lesser extent. In order to shorten process time, reduce synthesis cost, and prepare high performance cathode materials, layered LiNi1/3Mn1/3Co1/3O2 powders were synthesized by two methods, respectively, one is the solution combustion process with hexamethylenetetramine as a fuel and the other is the microwave method followed by short duration high temperature calcination. After determining optimal preparation conditions, cathode materials synthesized under these conditions and surface treated separately with different metal oxides to enhance cycle stability using a simple mechano-thermal coating procedure. Electrochemical studies revealed that both methods needed only a third of the process time to synthesize a LiNi1/3Mn1/3Co1/3O2 cathode compared to a conventional co-precipitation route. After surface modification, all the LiNi1/3Mn1/3Co1/3O2 powders coated with Al2O3 have showed improved cyclabiliy, indicating that coating materials can stabilize the cathode structure by suppressing characteristic structural phase transitions. Moreover, the mechano-thermal coating process is a simple, inexpensive, environmentally benign and commercially viable for producing high-cycling LiNi1/3Mn1/3Co1/3O2 cathode materials. ; 研究期間 9701 ~ 9712
