Principal Investigator Yet-Ming Chiang
Co-investigator Donald Sadoway
LiMn2O4 spinel and the monoclinic and orthorhombic polymorphs of LiMnO2 are widley studied as intercalation cathodes for rechargeable lithium batteries. Cation order, especially in LiMnO2, can change during electrochemical cycling with significant influence on the electrochemical properties. In this study, the magnetic properties of phases varying in Li/Mn ratio and cation ordering, produced by varying synthesis conditions or by electrochemical cycling, were studied using SQUID magnetometry. In the paramagnetic temperature regime, these antiferromagnetic phases differ in the magnitude of the Curie and Weiss constants. At lower temperature, frequency- and time-resolved measurements show characteristics of spin-glass behavior in all materials studied. This is attributed to geometric frustration and randomness due to cation disorder, which appears to co-exist with antiferromagnetic ordering in these materials.