Fast ionic conductors based on cadmium nitrate inclusion complexes of zeolite a and their high temperature treated forms

Abstract

The electric conductivity of zeolites increases with inclusion of salt into the cages of zeolite structure, In the case of cadmium nitrate inclusion complex Na22-2xCdx(NO3)10 (Al2O3)12 (SiO2)12 there is an optimum Cd2+ ion concentracion (x=4) at which the conductivity is highest. The thermal stability of the inclusion complex is limited by thermal stability of the included nitrate. During high temperature treatment the denitration and the decomposition of the zeolite framework with the formation of new crystalline phases occurs, whereby the conductivity is changed. In the case of cadmium content x≤4, the low-carnegieite phase was predominating and the samples showed the characteristics of good ionic conductors with a linear change of the conductivity in a wide temperature range and an activation energy of 58.6 kJ/mol. At higher cadmium contents the Monteponite and Nepheline phases were predominant and the ionic conductivity was decreased. © 1990.