简化的溶胶凝胶法合成LiMn_(2-x)La_xO_4及电性能研究  

Preparation and Electrochemical Performance of La-Doped LiMn_(2-x)La_xO_4 by Sol-Gel Method

作　　者：李翠翠[1] 陈刚[1] 张彬[1] 和广庆[1] 刘振琦[1] 

机构地区：[1]哈尔滨工业大学应用化学系,黑龙江哈尔滨150001

出　　处：《中国稀土学报》2009年第1期156-160,共5页Journal of the Chinese Society of Rare Earths

基　　金：黑龙江省自然科学基金资助项目(20871036)

摘　　要：采用以水溶液作为反应介质的简化的溶胶凝胶法制备了LiMn2O4和稀土La掺杂的LiMn1.98La0.02O4粉体材料,此方法工艺简单,容易控制,制备周期短。利用XRD,SEM对材料粉体进行结构形态表征,并以合成的材料为正极活性材料测试其充放电性能、循环伏安性能、电化学阻抗谱性能。实验结果表明:材料LiMn2O4和LiMn1.98La0.02O4具有较好的尖晶石结构,且颗粒分布均匀,掺杂La的材料循环性能有较大改善。以LiMn2O4为正极活性物质的扣式电池首次放电比容量129.38 mAh.g-1,循环20次后容量保持在94%,以LiMn1.98La0.02O4为正极活性物质的扣式电池首次放电比容量106.77 mAh.g-1,循环20此后容量保持在96.2%。The spinel lithium manganese oxide LiMn2O4 and LiMn1.98 La0.02 O4 doped with rare earth element were synthesized by sol-gel Method. The simple, cheap soft synthesis routine was easy to control at a short-term period. The chemical characterization of the materials was examined by X-ray diffraction and scanning electron microscopy （SEM）. Their electrochemical properties were investigated by cyclic voltammetry （CV）, galvanostatic electro-chemical impedance charge-discharge tests and spectroscope （EIS）. The results indicated that the La-ion doping did not affect the structure of the material, but considerably improved its cycle performance. The initial discharge capacity of LiMn2O4 reached 129.38 mAh.g^-1, and its discharge capacity remained 94% after 20 cycles. The initial discharge capacity of LiMn1.98 La0.02 O4 reached 106.77 mAh.g^-1 and its discharge capacity remained 96.2% after 20 cycles . The results showed that the rare earth ion could partially replace Mn^3＋ in the spinel sample and improve its cycle stability.

关 键 词：尖晶石型锰酸锂 溶胶凝胶法 镧掺杂 稀土 

分 类 号：TM912.9[电气工程—电力电子与电力传动]