Characterization of the thermal behavior of Li-Fe-tartrate gels (molar ratio Li/Fe <= 1/5)

摘要

The differential thermal analysis/thermogravimetric analysis characteristics of Li-Fe xerogels prepared by the tartrate gel technique are examined. Monophase lithium ferrospinel powders can be obtained by adjusting the calcining temperatures at 200-300 degreesC and 550 degreesC for the xerogel, if alpha -Fe2O3 was absent during the processing. The former temperature range resulted from the thermal reaction of gamma -Fe2O3 with lithium. The latter was attributed to the thermal reaction of Li-containing gamma -Fe2O3 (Li-gamma -Fe2O3) with lithium. An increase in the amount of the former formed can substantially decrease that for the latter. The thermal reaction for forming lithium ferrite can be topotactic. More importantly, it may be triggered by the phase transformation. (C) 2001 Academic Press. [References: 37]