Abstract:ThetransportpropertiesofionsinNi(OH)2electrochromicfilmswerestudiedinthisarticle.ThediffusioncoefficientDoftheionsinthefilmswasmeasuredbythecyclicvoltammograms.ThedependenceofDontemperatureshowsthatthetransportationofionsishoppingthroughthegrainboundary.Theelectrochromicphenomenaisabulkeffectbutnotasurfaceeffect.IntheNi(OH)2(solid)/NaOH(liquid)systemusedinthisstudy,theinterfaceisveryimportantwhichaffectthetransportationofionsandthustheelectrochromicpropertiesofthefilms.