(中南大學 冶金科學與工程學院，長沙 410083)
摘 要: 采用固相法在鋰離子電池正極材料LiCoO2表面包覆一層LiFePO4；研究了LiFePO4包覆量對材料性能的影響；采用X射線衍射儀和掃描電鏡分析樣品的晶體結構和表面形貌。研究結果表明：樣品具備LiCoO2的α-NaFeO2型層狀結構，但隨著包覆量的增加，XRD衍射譜顯示樣品存在多種雜相；合成的樣品電化學性能良好，當LiFePO4的包覆量為1%時，在室溫下以0.1C倍率充放電，首次放電比容量達145.9 mA·h/g，純相LiCoO2放電比容量為146.2 mA·h/g。樣品采用1C倍率放電時，首次放電比容量達138.9 mA·h/g，循環(huán)性能較好，經(jīng)過20次循環(huán)放電比容量僅衰減4.97%。
關鍵字: 正極材料；LiCoO2；LiFePO4
（School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China）
Abstract:LiCoO2 cathode materials were coated with LiFePO4 by the solid state reaction for lithium-ion batteries. The effects of LiFePO4 coating amount on properties of samples were studied. The crystalline structure and morphology of samples were analyzed by X-ray diffractometry and scanning electron microscopy, respectively. The results show that the samples own the α-NaFeO2 layered structure of LiCoO2. But with the increase of coating amount, XRD patterns show more impurity phases. The samples show excellent electrochemical performance. At room temperature, the specific discharge capacity of the sample coated with 1% LiFePO4 reaches 145.9 mA·h/g at 0.1C, while the specific discharge capacity of pure LiCoO2 reaches 146.2 mA·h/g. The specific discharge capacity at 1C reaches 138.9 mA·h/g. The materials show better cycle performance. The capacity only losts 4.97% after 20 cycles.
Key words: cathode material; LiCoO2; LiFePO4
