The ionic conductivity of sodium chalcogenide or chalcohalide glasses is 2 to 3 orders of magnitude higher than that of oxide glasses and comparable with lithium ionic conductivity. This makes sodium chalcogenide systems suitable for applications in power rechargeable systems. More importantly, the sodium batteries appear to be a good alternative to lithium systems extensively used in everyday life but limited by the fact that lithium is not an abundant element. In order to understand the relationship between the glass local and intermediate-range structure and the ionic transport, we are going to combine diffraction and spectroscopy measurements of sodium sulphide and selenide glasses with conductivity and diffusion studies, as well as structural modelling using DFT.