LiMn2O4具有價格低、能量密度高及低毒性等優點，成為最具潛力取代傳統應用於鋰離子二次電池中LiCoO2的正極材料。本實驗利用Pechini法合成LiMn2O4，可獲得初始放電電容量佳之粉末，而LiMn2O4在充放電循環時，具電容量衰退之問題，可利用表面改質方法來穩定粉末結構及性質。

　　利用Pechini合成法經連續爐熱處理之LiMn2O4粉末，其放電電容量偏低，配合後熱處理之LiMn2O4粉末(LMO800)，其放電電容量有明顯提升，連續爐熱處理合成之LiMn2O4粉末，其初始放電電容量僅84mAh/g，經後熱處理，LMO800其初始放電電容量為124 mAh/g，經XRD及錳價數滴定分析，可知經後熱處理，LiMn2O4粉末其結晶度變佳，且錳平均價數接近理論值3.5，推論粉末初始放電電容量可能跟粉末結晶度及錳價數有關。

　　LMO800在55℃充放電循環測試時，其放電電容量明顯衰退，本實驗利用Pechini合成法將鋰鎳離子修飾在LMO800粉末表面上，經熱處理，可改善LMO800粉末在25℃及55℃下之充放電電容量衰退特性。LMO800粉末在25℃下進行充放電循環測試，經50cycles後，保有88%初始電容量；利用鋰鎳離子表面改質後，保有95%的初始電容量；而在55℃下進行充放電循環測試，經50cycles後，僅剩70%初始電容量；表面改質後，仍保有94%的初始電容量。利用ICP、XPS及EDS分析，可知表面改質後，粉末表面形成一層鋰鎳錳氧化物，隔離了粉末內部與電解液接觸，可有效抑制錳離子在電解液中析出。

　Spinel phase LiMn2O4 has been considered to replace LiCoO2 cathode material for lithium-ion rechargeable batteres because of its lower cost, high energy density and lower toxicity. The purpose of this study is to enhance the capacity by using the Pechini process and decrease the capacity fading effectively by surface modification of LiMn2O4 cathode material.

　Using Pechini process through the continuous stove heat treatment has been developed to synthesize LiMn2O4 powders. For the purpose to acquire completely LiMn2O4 powders, a post heat treatment should be performed. The powders (LMO800) with post heat treatment have superior discharge capacity. Through analyzing by XRD and manganese valence titration, it could be found that an increase in the crystallinity of the LiMn2O4 powders and manganese average valence of powders close to 3.5 after post heat treatment. The initial discharge capacity may be related to the crystallinity of the powders and manganese valence.

　In this study, the surface of LiMn2O4 (LMO800) was covered with lithium nickel manganese oxide prepared by the Pechini process. After 50 cycles at 25℃, the bare LiMn2O4 showed 88% of the initial discharge capacity and surface-modified LiMn2O4 showed 95% of the initial discharge capacity. After 50 cycles at 55℃, the bare LiMn2O4 showed only 70% of the initial discharge capacity and surface-modified LiMn2O4 showed 94% of the initial discharge capacity. Thus, electrochemical performance of the LiMn2O4 can be improved by the surface modification with Li-Ni-ion. This action improves cyclability for lithium battery performance and reduces capacity fades of LiMn2O4 at elevated temperatures. Through analyzing by ICP, XPS and EDS, it can be explained by suppression of Mn dissolution in the electrolyte.

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