低含量锰掺杂Li2FeSiO4/C作为锂离子电池正极材料的电化学性能  

Electrochemical performance of low content Mn-doped Li2FeSiO4/C cathode materials for lithium-ion batteries

作　　者：赵永男[1,2] 郭敏[1,2] 高海燕 邓雪莹[1,2] 高国伟 张李安妮 王宇萌 ZHAO Yong-nan;GUO Min;GAO Hai-yan;DENG Xue-ying;GAO Guo-wei;ZHANG Li-an-ni;WANG Yu-meng(Tianjin Key Laboratory of Advanced Fibers and Energy Storage,Tiangong University,Tianjin 300387,China;School of Material Science and Engineering,Tiangong University,Tianjin 300387,China;Key Laboratory of Advanced Energy Materials Chemistry,Ministry of Education,Nankai University,Tianjin 300071,China)

机构地区：[1]天津工业大学天津市先进纤维与储能技术重点实验室,天津300387 [2]天津工业大学材料科学与工程学院,天津300387 [3]南开大学先进能源材料化学教育部重点实验室,天津300071

出　　处：《天津工业大学学报》2020年第6期53-60,共8页Journal of Tiangong University

基　　金：国家自然科学基金资助项目(21703152);天津市自然科学基金资助项目(17JCQNJC06100);天津市教委科研计划项目(自然科学)(2018KJ197);南开大学先进能源材料化学教育部重点实验室开放课题。

摘　　要：为提高Li2Fe1-x SiO4/C正极材料的电化学性能,采用溶胶-凝胶法制备了一系列Mn掺杂的Li2Fe1-x MnxSiO4/C(x=0,0.02,0.04,0.06)复合材料;利用X射线粉末衍射仪(XRD)、场发射扫描电子显微镜(FESEM)、高分辨率透射电子显微镜(HRTEM)等方法对材料的物相和形貌进行了表征。结果表明:所有样品均为(P21/n)对称性的单斜晶体结构,形貌保持为类球形,Mn掺杂使得材料具有更小的粒径尺寸;Li2Fe0.96Mn0.04SiO4/C具有最佳的电化学性能,在0.1 C、0.5 C、1 C和3 C的电流密度下,该材料的放电比容量分别为232.9、188.6、176.5和140.3 mA·h/g。在0.2 C的电流密度下,充放电循环150周后,放电比容量仍为170 mA·h/g,容量保持率为87.13%。In order to improve the electrochemical performance of Li2Fe1-xSiO4/C cathode materials,a series of Mn doped Li2Fe1-xMnxSiO4/C(x=0,0.02,0.04,0.06)composites were prepared by a sol-gel method.X-ray powder diffractometer(XRD),Field emission scanning electron microscopy(FESEM),High resolution transmission electron microscope(HRTEM)and energy-dispersive X-ray spectroscope(EDX)were used to characterize the phase and morphology of the materials.The results show that all the samples show P21/n symmetrical monoclinic crystal structure,the morphology keeps well after doping.Proper content of Mn doping reduces the particle size and shows better electrochemical performance.Li2Fe0.96Mn0.04SiO4/C shows the best electrochemical performance,with 232.9,188.6,176.5,and 140.3 mA·h/g at 0.1 C,0.5 C,1 C,3 C,respectively.After 150 cycles at 0.2 C,it remains at 170 mA·h/g with capacity retention of 87.13%.

关 键 词：锰掺杂 正极材料 溶胶凝胶 锂离子电池 

分 类 号：O646[理学—物理化学] O614.111[理学—化学]