The invention discloses an electrochromic device of the type comprising at least one substrate and a structure of at least partly superimposed layers, where the structure comprises at least one layer of electrochromic material and a layer of electronic insulating transparent ion-conducting solid electrolytic material, and where at least one of these layers is nanostructured, i.e. has a nanostructure. Possible uses of these electrochromic devices are for controlling the energy of the electromagnetic waves reflected by the device or transmitted through the device, for example, a rear-view mirror or a motor vehicle window glass.