摘要
The phase transition of Li2Mn2O4 spinel at high temperature was investigated by XRD, TG/DTA, average oxidation state of Mn and cyclic voltammeric techniques. The results reveal that the Li2Mn2O4 spinel is unstable. At high temperature, it is easy to transform into [Li2-2x]tet[Mn2-xLix]octO4, which accompanies the formation of Li2MnO3 impurities. The phase transition is associated with the transfer of Li+ from tetrahedral 8a sites to octahedral 16d sites. With the increasing sintering temperature from 450 ℃ to 850 ℃, the phase structure varies from lithiated-spinel Li2Mn2O4 to Li4Mn5O12-like to LiMn2O4-like and finally to rock-salt LiMnO2-like. In addition, a way of determining x with average oxidation state of Mn and the content of Li2MnO3 was also demonstrated.
The phase transition of Li2Mn2O4 spinel at high temperature was investigated by XRD, TG/DTA, average oxidation state of Mn and cyclic voltammeric techniques. The results reveal that the Li2Mn2O4 spinel is unstable. At high temperature, it is easy to transform into [Li2-2x]tet[Mn2-xLix]octO4, which accompanies the formation of Li2MnO3 impurities. The phase transition is associated with the transfer of Li^＋ from tetrahadral 8a sites to octahedral 16d sites. With the increasing sintering temperature from 450 ℃ to 850 ℃, the phase structure varies from lithiated-spinel Li2Mn2O4 to Li4Mn5O12-like to LiMn204-like and finally to rock-salt LiMnO2-like. In addition, a way of determining x with average oxidation state of Mn and the content of Li2MnO3 was also demonstrated.
出处
《中国有色金属学会会刊：英文版》
EI
CSCD
2006年第2期438-444,共7页
Transactions of Nonferrous Metals Society of China
基金
Project(20406024) supported by the National Natural Science Foundation of China
Project(76600) supported by the Postdoctoral Science Foundation of Central South University, China
关键词
Li2Mn2O4
锂离子电池
高温
相变
lithium manganese oxide
Li2Mn2O4
phase transition
lithium-ion batteries
