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.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
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~~
