Abstract :
Lithium loss from LixCo1−xO solid solutions at 1200°C was investigated by diffractometric (XRD) and gravimetric measurements. The results of XRD 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 isothermal treatment. This dimensionless parameter is related to the evaporation 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 solid solution with x about 0.06 seems to be stable against lithium loss. Experimental weight loss, due to both lithium loss and LixCo1−xO stabilization against phase transition, was compared with calculated weight loss using the parameters obtained from XRD analysis.
