锂离子电池正极材料LiMn_(2-x)Sr_xO_4的制备与电化学性能研究  

Synthesis and Electrochemical Performance of Sr-doped Spinel lithium Manganese Oxides

作　　者：李超[1] 毕磊[1] 许炎妹[1] 吴诗德[1] 樊彦良[1] 徐甲强[1] 

机构地区：[1]郑州轻工业学院材料与化学工程学院,河南郑州450002

出　　处：《中国锰业》2007年第3期38-41,共4页China Manganese Industry

基　　金：河南省青年骨干教师资助计划(2004)资助项目;河南省杰出青年科学基金(0612002700)

摘　　要：采用固相分段煅烧的方法合成了具有尖晶石结构的锂离子电池正极材料LiMn2-xSrxO4(x=0.0、0.05、0.1),并利用X射线衍射、IR光谱、SEM、充放电、交流阻抗测试对材料进行了表征。结果表明,所合成的锶掺杂改性材料仍具有标准的尖晶石结构,但结晶度有所下降,晶格发生收缩。当x=0.05时,掺杂锶的改性材料LiMn2-xSrxO4具有优异的循环性能,在0.2 C放电速率下,其首次放电容量为116.4 mAh/g,循环20次后,容量保持率超过98%。少量锶的掺杂能使材料循环性能得到大副提高,与锶掺杂引起的结构稳定性提高有关,这说明改善材料结构稳定性对抑制循环过程中容量衰减有重要作用。Sr-doped spinel lithium manganese oxides cathode materials LiMn2-xSrxO4（x=0.0、0.05、0.1）were synthesized by solid state reaction and two-step calcinations.Testing of XRD,IR spectrum,SEM,charge-discharge and AC impedance methods were carried out for the synthesized materials.Results reveal that the Sr-doped materials exhibit standard spinel structure,but the crystallinity is reduced and the crystal cell shrinks.The LiMn2-xSrxO4 materials show excellent cycle performance when x=0.05.The sample shows with a first discharge capacity of 116.4 mAh/g and retains more than 98% of the initial capacity after 20 cycles at the current rate 0.2 C. A little amount of Sr doping can dramatically enhance the cycle performance of spinel lithium manganese oxides cathode materials, which reveals that doping Sr plays an important role of improving the stability of spinel structure and restraining the capacity fading.

关 键 词：锂离子电池 正极材料 循环性能 交流阻抗 

分 类 号：TM912.9[电气工程—电力电子与电力传动]