锂离子电池正极材料LiNi_(0.5)Fe_xMn_(1.5-x)O_4的电化学性能

Electrochemical Properties of LiNi_(0.5)Fe_xMn_(1.5-x)O_4 as Cathode Materials for Lithium-ion Batteries

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。

Abstract The 4. 6 V high potential materials LiNi0.5FexMn1.5-xO4 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 of n（Li）：n（Mn）：n（Ni）：n（Fe）=1.3：1.5-x：0.5：x（x=0,0.02,0.03,0.04）, and subsequently 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 electron microscopy. The initial charge-discharge performances and cycle efficiencies were tested. The experimental results showed that the high potential materials LiNi0.5FexMn1.5-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 126mA·h·g^-1.