摘要
用高精度非原位XRD结合Rietveld精修对正交Li1-xMnO2(简写为o-Li1-xMnO2,0≤x≤0.95)在首次充电(电化学脱锂)过程中物相及结构的演变进行了研究。结果表明,o-LiMnO2电极的电压升高速率与其结构的变化有关;随着电化学脱锂o-LiMnO2发生一系列相变。证实了文献的理论计算和由晶体学推测出的相变过程,即相变产物中先后出现岩盐型锰酸锂和类尖晶石型锰酸锂。相变结束后,产物中只有岩盐型和类尖晶石锰酸锂2种物相。随着充电的进行,都有Li+从岩盐型和类尖晶石锰酸锂晶格中脱出,二者晶胞参数逐渐变小,微结构也不断变化。
Phase transformation of layered orthorhombic Li1-xMnO2（o-Li1-xMnO2,0≤x≤0.95） during the first charging process（lithium ion deintercalation in electrochemical system） was investigated using ex-situ high-resolution X-ray diffraction and Rietveld refinement.The results reveal that the increasing speed of the o-LiMnO2 cathode＇s voltages is related to the change of its microstructure.And a succession of phase transformation of the o-LiMnO2 occurs in the first lithium deintercalation process.Rock-salt typed lithium manganese oxides emerge followed by the appearance of the spinel-like typed,which confirms the phase transition process from theoretical computation and crystallography conjecture in literatures.Only the above-stated type lithium manganese oxides（originated from o-LiMnO2） exist in the final product.Lithium ions extract from lattices of the rock-salt typed and the spinel-like typed lithium manganese oxides;both the lattice parameters become smaller and their microstructures change with the charge proceeding.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2011年第3期424-428,共5页
Rare Metal Materials and Engineering
基金
河南省教育厅自然科学研究项目(2009A430010)
河南理工大学博士基金(B648238)
关键词
正交LiMnO2
充电过程
相变
结构演变
orthorhombic LiMnO2
charging process
phase transformation
microstructure evolution
