富锂尖晶石Li_(1+x)Mn_(2-x)O_4的合成与性能

Synthesis and performance of lithium-rich spinels Li_(1+x)Mn_(2-x)O_4

将MnO2和Li2CO3通过固相反应法合成了化学计量比的LiMn2O4和富锂型Li1+xMn2-xO4(x=0.02,0.04,0.06,0.08,0.1)。研究表明,所合成的样品均具有尖晶石结构,无杂相存在,样品的晶格常数随x值的增大而减小。用SEM分析了样品的表面形貌,发现掺锂可明显改善LiMn2O4一次颗粒表面的结构,抑制表面裂纹的产生。电化学性能测试表明,随着掺锂量的提高,电极的循环性能变好。通过研究发现,Li1.04Mn1.96O4具有较高的初始容量和良好的循环性能,因而,Li1.04Mn1.96O4是一种比较理想的锂离子电池正极材料。

Stoichiometric and lithium-rich spinels Li_1+xMn_2-xO_4(x=0, 0.02, 0.04, 0.06, 0.08, 0.1) were synthesized with MnO_2 and Li_2CO_3 through solid-state reaction. The results show that the samples synthesized have spinel structure, and there are not other phases in samples. The microstructures of the samples were measured by scanning electron microscope. It shows that the surface structure of the primary particles is clearly improved, with less crack after lithium-doping. The measurement of electrochemical properties shows that the cycle ability and rate capability are also improved with the doping of lithium, which show that lithium-rich spinel Li_1.04Mn_1.96O_4 is a promising cathode material for lithium ion batteries with good cycle ability and rate capability.