Impedance spectroscopy was used to investigate the long-range ionic conductivity of the microporous, titanosilicate (Na,K)-ETS-10 and ion-exchanged Mn+-ETS-10 (where, Mn+ = Li+, Na+, Mg2+, Zn2+, Ca2+) thin films prepared by secondary growth method. To figure out the effect of grain boundary on ionic conduction, as-synthesized (Na,K)-ETS-10 films possessing different thicknesses of columnar grain structure (i.e., films prepared via 4h-, 6h-, 8h-, and 10h-growth) were tested. The conductivities of the films with different thicknesses at 723 K were in the range of similar to 10(-3) Omega(-1)cm(-1). However, activation energies of the films decreased from 52.8 to 47.3 kJ mol(-1) (i.e., 0.6 to 0.5 eV) for 4h-(Na,K)-ETS-10 to 10h-(Na,K)-ETS-10 films, respectively. The as-synthesized (Na,K)-ETS-10 film prepared via 6h-growth (denoted as (Na,K)-6h-ETS-10) and monovalent cation-exchanged samples Li- and Na-6h-ETS-10 films exhibit conductivities of 2.1 x 10(-3), 2.4 x 10(-4), and 2.7 x 10(-4) Omega(-1)cm(-1), respectively, at 723 K and activation energies of 50.1, 55.5, and 55.4 kJ mol(-1), respectively, in the temperature range 573-773 K. Divalent cation-exchanged samples Mg-, Zn- and Ca-6h-ETS-10 films exhibit conductivities of 2.3 x 10(-4), 2.9 x 10(-4), and 8.8 x 10(-5) Omega(-1)cm(-1), respectively, at 723 K and activation energies of 62.5, 57.9, and 65.2 kJ mol(-1), respectively, in the temperature range 573-773 K. The data shown here indicate that ionic conductivity of intergrown (Na,K)-ETS-10 films prepared by secondary growth method were significantly enhanced with respect to pressed pellets of powder zeolite and zeo-type materials which imply the importance of engineering the microstructure of the zeolite film to improve the conductivity of zeolites and zeo-type materials. (C) 2017 Elsevier Inc. All rights reserved.