(\mathrm{LiNaSO}{4}: \mathrm{LiCl}: \mathrm{Na}{2} \mathrm{WO}{4}) composites of a few different compositions have been prepared by quenching the melt and studied for the first time with a view to improve the ionic conductivity of (\mathrm{LiNaSO}{4}) at the lowest possible temperature. The phase formations of the composites have been analyzed by means of X-ray powder diffraction technique. The transport properties have been studied by DSC and complex ac impedance analysis (to extract the dc electrical conductivity, (\sigma_{\mathrm{dc}}) ). The X-ray diffractograms show evidence for solid solutions ( (\mathrm{ss}) ) as well as a second dispersed phase due to undissolved excess compound ( (\mathrm{LiCl}) ). The (\sigma) enhancement may be attributed to the increase in interfacial conductivity due to the increase in concentration of the charge carriers (ions or vacancies) forming a diffuse space charge layer between the two ion conductors, i.e., the solid solution of (\mathrm{LiNaSO}{4}) with dissolved chloride and tungstate fractions and a chloride phase with dissolved sulfate fraction. DSC measurements show improved thermal properties with respect to (\alpha-\mathrm{LiNaSO}{4}). The present composite mixtures offer the choice of lower transition temperatures, but these are accompanied by lower transition enthalpies. O 1993 Academic Press, Inc.