On the thermal stability and defect structure of the solid solution LixNi1-xO
Abstract Li x Ni 1- x O solid solutions are both of scientific and technological interest as they have been proposed as cathodic material in MCFC. In this work TG, XRD and SEM measurements have been used to study the thermal stability of several solid solutions (of different initial composition) obtained starting from the reactive system Ni/Li 2 CO 3 . Composition changes, due to both lithium and oxygen loss, take place as a consequence of samples annealing. In some cases a sensible disagreement between the compositions deduced by TG and XRD data is showing, which is ascribed to the presence, in the final solid solutions, of lattice defects others than substitutional ones (namely cation vacancies). The TG and XRD measurements have been then worked out to obtain both the correct composition and vacancies concentration of the solid solutions. It is shown that solid solutions with similar lithium content but different vacancies concentration can be obtained depending on the preparation conditions.