A team at Argonne has made important strides in resolving this issue with a new design for a sodium-ion oxide cathode ... National Synchrotron Light Source II (beamline 18-ID) at DOE's Brookhaven ...

its freshly exposed shiny surface rapidly turns dull as a thin layer of sodium oxide forms: Other metals may oxidise more slowly. Gold and other very unreactive metals do not oxidise in air at all.