Li2O evaporation from LixCo1-xO solid solutions at 1200 degrees C

Lithium loss from LixCo1-xO solid solutions at 1200 degreesC was investigat ed by diffractometric (XRD) and gravimetric measurements. The results of XR D analysis indicated that the time dependence of Li2O evaporation from the solid solutions was 0.2 for a nominal Li 10% sample, while for a nominal Li 20% sample, the time dependence changed from 1 to 0.2 following 5 h of iso thermal treatment. This dimensionless parameter is related to the evaporati on mechanism. The behaviour of the nominal Li 20% sample was related to the presence of layered LiyCo2-yO2 solid solution in the external part of the particles. Lithium content of the solid solution attained a constant value of 0.06, independent of nominal lithium content of the sample. Then, the so lid solution with x about 0.06 seems to be stable against lithium loss. Exp erimental weight loss, due to both lithium loss and LixCo1-xO stabilization against phase transition, was compared with calculated weight loss using t he parameters obtained from XRD analysis. (C) 2001 Elsevier Science Ltd and Techna S.r.l. All rights reserved.