镁掺杂对正极材料尖晶石LiMn_2O_4电化学性能的影响  

Influence of magnesium doping on the electrochemical performance of spinel LiMn_2O_4 anode material

作　　者：吴瑞峰[1] 叶金云[1] 胡启山[2] 周建庭[3] 

机构地区：[1]郑州旅游职业学院机电工程系,郑州450009 [2]四川文理学院化学与工程技术学院,达州635000 [3]重庆交通大学材料科学与工程学院,重庆400074

出　　处：《化工新型材料》2017年第5期164-166,172,共4页New Chemical Materials

基　　金：河南省科技厅软科学项目(142400411009);达州市科技局项目(KJJ2015002);国家自然科学基金资助项目(51278512);国家杰出青年基金资助项目(51278512)

摘　　要：为了抑制Jahn-Teller效应导致的结构畸变对锂离子电池正极材料LiMn_2O_4结构的影响,通过溶胶-凝胶法成功制备出了尖晶石LiMn_2O_4和镁离子掺杂的LiMg_(0.1)Mn_(1.9)O_4样品。并用X射线衍射、扫描电镜、充放电测试、X射线能谱、循环伏安对样品结构、形貌和电化学性能进行研究,发现适量的镁离子掺杂未改变LiMn_2O_4的结构。在0.5C倍率下,LiMg_(0.1)Mn_(1.9)O_4样品的首次放电比容量稍有降低,但循环100次后,容量保持率高达93.8%,远高于未掺杂镁样品的容量保持率(75.8%);在5C倍率下,LiMg_(0.1)Mn_(1.9)O_4的放电比容量高达91mAh/g,而未掺杂的样品仅为72.9mAh/g。结果表明:镁离子掺杂可以有效抑制Jahn-Teller畸变,改善LiMn_2O_4的电化学性能。In order to suppress the Jahn-Teller distortion in spine LiMn2O4 , the samples of LiMn2O4 and LiMg0.1 Mn1. 9 04 were synthesized by sol gel reaction route. The effects of magnesium on the structure, morphology and electro chemical performances of LiMn2O4 were studied by XRD, SEM, galvanostatic charge-discharge, XPS and CV, respectively. The results suggested that doping used appropriate amount of magnesium didn＇t change the spinel structure of LiMn2O4. The LiMg0.1 Mn1.9O4 had lower initial discharge capacity compared with that of LiMn2O4, but the capacity retention was still as high as 93.8% even after 100 cycles at a rate of 0.5C. The discharge capacity of LiMg0.1Mn1. 904 was 91 mAh/g, which higher than that of LiMn2O4 （72.9mAh/g）. Thus,the doping of magnesium was a very effective way to suppress the Jahn-Teller distortion and improved LiMn2O4 electrochemical performance.

关 键 词：锂离子电池 正极材料 溶胶-凝胶法 镁离子掺杂 电化学性能 

分 类 号：TM912[电气工程—电力电子与电力传动]