LiNi_(0.5)Mn_(1.5)O_4在不同电解液中的电化学性能  

Electrochemical performances of LiNi_(0.5)Mn_(1.5)O_4 in different electrolytes

作　　者：徐根华[1] 何建忠[1] 高良超[2] 王嘉丽[2] 崔永丽[2] 

机构地区：[1]江苏中金玛泰医药包装有限公司,江苏连云港220047 [2]中国矿业大学材料科学与工程学院,江苏徐州221116

出　　处：《电源技术》2014年第7期1227-1230,共4页Chinese Journal of Power Sources

基　　金：中央高校基本科研业务费专项基金(2010LKHX03;2010QNB04;2010QNB05);江苏高校优势学科建设工程资助项目;江苏省大学生实践创新训练计划(S102901231);江苏省博士后科研资助计划项目(1201030C)

摘　　要：利用溶胶凝胶法合成4.7 V高电压正极材料LiNi0.5Mn1.5O4,运用X射线衍射(XRD)和扫描电子显微镜(SEM)对其结构与形貌进行表征,并测试了其在1 mol/L LiPF6/(EC+DEC)、1 mol/L LiPF6/(EC+DEC+DMC)、1 mol/L LiPF6/(EC+EMC)三种电解液中的充放电性能。研究发现,不同成分的电解液显著影响LiNi0.5Mn1.5O4材料的电化学性能,其中在1 mol/L LiPF6/(EC+EMC)电解液中,材料具有相对好的循环性能,其最大放电比容量为92.4 mAh/g,50周循环后,比容量衰减为68.4 mAh/g,容量保持率为74%。循环伏安曲线(CV)结果表明,在4.7 V附近出现两对强氧化还原峰分别对应于Ni2+/Ni3+和Ni3+/Ni4+,在4.0 V出现的弱氧化还原峰则对应于Mn3+/Mn4+。相比于4.0 V低电压,在4.7 V高电压下LiNi0.5Mn1.5O4电极的SEI膜电阻增大而锂离子的脱嵌更容易进行。High voltage of 4.7 V cathode material LiNi0.5Mn1.5O4 was prepared by sol-gel method. The structure and morphology were characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The charge-discharge performances of LiNi0.5Mn1.5O4 in three different electrolytes of 1 mol/L LiPF6/ （EC＋DEC）, LiPF6/ （EC＋DEC＋DMC） or LiPF6/（EC＋EMC） were tested. The research shows that different components electrolyte greatly effects electrochemical performance of LiNi0.5Mn1.5O4. The spinel LiNi0.5Mn1.5O4, cathode has best cycling performance in 1 mol/L LiPF6/（EC＋EMC）： maximum discharge specific capacity is 92.4 mAh/g; its capacity retention is 74% after 50 cycles with specific capacity of 68.4 mAh/g. The CV curves show that there are two couples of strong redox peaks at 4.7 V attributing to Ni2＋/NP＊, Ni3＋/Ni4＊and a pair of weak peak at 4.0 V attributing to Mn3＋/Mn4＋. The resistance of SEI film of LiNi0.5Mn1.5O4 cathode at high voltage of 4.7 V is much higher than that at 4.0 V, so the lithium ion intercalation/de-intemalation becomes more easily.

关 键 词：LINI0 5Mn1 5O4 电解液 电化学性能 电化学阻抗谱 

分 类 号：TM912[电气工程—电力电子与电力传动]