锂离子电池正极材料LiNi0.5FexMn1.5-xO4的电化学性能

以醋酸锂、醋酸锰、醋酸镍、草酸铁为原料,采用溶胶凝胶法制备出了4.6 V高电位材料LiNi0.5-FexMn1.5-xO4。合成化学计量比为n(Li)∶n(Mn)∶n(Ni)∶n(Fe)=1.3∶1.5-x∶0.5∶x(x=0,0.02,0.03,0.04)。在空气条件下于450℃下煅烧6h,再于800℃下烧结18h。对合成的材料用X射线衍射仪分析晶体结构和用扫描电镜(SEM)观察微观形貌,对电池进行首次充放电测试和循环效率测试。实验结果表明,LiNi0.5FexMn1.5-xO4三元正极材料为立方晶系,Fd3m空间群。以其为正极材料组装的锂离子电池在x=0.03时,充放电比容量为126mA·h·g-1。

Electrochemical Properties of LiNi0.5 FexMn1.5-xO4 as Cathode Materials for Lithium-ion Batteries

The 4.6 V high potential materials LiNi0.5 FexMn1.5-x O4 was synthesized via sol-gel method using CH3COOLi·2H2O,Mn(CH3COO)2 ·4H2O,Ni(CH3COO)2 ·4H2O,Fe(C2O4)3 ·5H2O as raw materials at the molar ratio ofn(Li):n(Mn):n(Ni):n(Fe)=1.3:1.5 -x:0.5:x (x=0,0.02,0.03,0.04),and subsequent-ly preheated for 4 h at 450 ℃ within a atmosphere furnace and reheated at 800 ℃ for 18 h.The crystal structures of the cathode materials were analyzed through X-ray diffraction and the microstructures were observed by scanning elec-tron microscopy.The initial charge-discharge performances and cycle efficiencies were tested.The experimental re-sults showed that the high potential materials LiNi0.5 FexMn1.5-xO4 were cubic crystal with Fd3m space group,and the Li-ion battery fabricated by the cathode material with x=0.03 exhibited an initial discharge capacity of 126 mA·h· g-1.