Ge^(4+)、Sn^(4+)掺杂尖晶石LiMn_2O_4的合成与电化学表征  

Synthesis and Electrochemical Characterization of Ge^(4+),Sn^(4+) Doped Spinel LiMn_2O_4

作　　者：熊礼龙[1] 徐友龙[1] 陶韬[1] 

机构地区：[1]西安交通大学电子陶瓷与器件教育部重点实验室和国际电介质研究中心,西安710049

出　　处：《物理化学学报》2013年第4期763-769,共7页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(21203145)资助项目~~

摘　　要：使用Ge4+、Sn4+作为掺杂离子,通过高温固相法制备四价阳离子掺杂改性的尖晶石LiMn2O4材料.X射线衍射(XRD)和扫描电子显微镜(SEM)分析表明,Ge4+离子取代尖晶石中Mn4+离子形成了LiMn2-xGexO4(x=0.02,0.04,0.06)固溶体;而Sn4+离子则以SnO2的形式存在于尖晶石LiMn2O4的颗粒表面.Ge4+离子掺入到尖晶石LiMn2O4材料中,抑制了锂离子在尖晶石中的有序化排列,提高了尖晶石LiMn2O4的结构稳定性;而在尖晶石颗粒表面的SnO2可以减少电解液中酸的含量,抑制酸对LiMn2O4活性材料的侵蚀.恒电流充放电测试表明,两种离子改性后材料的容量保持率均有较大幅度的提升,有利于促进尖晶石型LiMn2O4锂离子电池正极材料的商业化生产.Spinel LiMn2O4 materials doped with tetravalent cations Ge4＋ and Sn4＋ were synthesized through solid-state reaction.Analysis of the materials by X-ray diffraction（XRD） and scanning electron microscopy（SEM） suggested that Ge4＋ ions occupied octahedral sites by substituting Mn4＋ ions in the spinel structure to form the solid solution LiMn2-xGexO4（x=0.02,0.04,0.06）,while Sn4＋ ions were present at the surface of the spinel LiMn2O4 as SnO2.The substitution of Mn4＋ with Ge4＋ could suppress the long-range ordering of the Li＋ ions in the spinel LiMn2O4,enhancing its stability.SnO2 on the surface of LiMn2O4 could reduce the acidity of the liquid electrolyte,suppressing acid etching of the LiMn2O4 active material.Galvanostatic charge/discharge tests showed that both Ge4＋ and Sn4＋-modified spinel LiMn2O4 materials exhibited significantly higher capacity retention than LiMn2O4.The increased capacity retention should benefit the application of spinel LiMn2O4 as a cathode material for lithium-ion batteries.

关 键 词：尖晶石LIMN2O4 锗掺杂 锡掺杂 固相反应 循环性能 

分 类 号：TM912[电气工程—电力电子与电力传动]