LiAl_yNi_(1-y)O_2作为锂离子电池正极材料的研究

Studies of the LiAl_yNi_(1-y)O_2 as Cathode Materials for Rechargeable Lithium Ion Batteries

本文采用固相反应法合成了一系列不同 y值的LiAlyNi1- yO2 材料 ,通过对其电化学性能的研究发现 ,在适当的烧结条件下 ,LixAl0 .2 5 Ni0 .75 O2 作为二次锂离子电池的正极材料 ,其耐过充性和循环性能都有明显改善 .当Li含量大于 1时 ,在高电位范围充放 (3- 4 .8V) 30次循环后仍保持着首次放电容量的 95 % ,而LiNiO2 在此电压范围内经 2 0次循环后却只有首次放电容量的 5 6 % .通过循环伏安实验表明 :性能改善的主要原因可能是由于充电过程中 ,Al3+ 的掺杂阻止了LixAl0 .2 5Ni0 .75 O2 随Li+ 离子过量脱出而发生晶型转变 .

In this paper, we have synthesized series of single_phase LiAl yNi 1-y O 2 (differentive in value_y) by solid reaction. Through examining their electrothemical properties, found that, under a proper sintering condition, Li xAl 0.25 Ni 0.75 O 2 solution for cathode materials of rechargeable lithium ion batteries showed more pleasing properties in overcharge_resist and cycling life ( vs LiNiO 2). When x>1, the capacity can be kept 125mAh/g after 30 cycles under higher charged/discharged voltages ranging from 3.0 V to 4.8 V, whereas that of pure LiNiO 2 has only 61 nAh/g after 25 cycles. The results of CV for LiAl yNi 1-y O 2 and pure LiNiO 2 showed that this may be due to the Al 3+ doping and by preventing Li + from overcharging, Al 3+ conbined with Li + obviated the phase transmission during charged/discharged progress.