An improved cathode is described which comprises an air-permeable, top coat deposited on the face of the cathode current collector screen. The top coat contains a CO.sub.2 absorber such as magnesium hydroxide which absorbs CO.sub.2 from the air and prevents CO.sub.2 from reacting with or neutralizing the electrolyte. The layer is composed of a dispersion of metal hydroxide in a hydrophobic binder such as polytetrafluoroethylene. The top coat is preferably formed of a first, outer gas flow limiting layer of hydrophobic material absent any CO.sub.2 absorber and a second, inner layer adjacent the current collector of hydrophobic binder containing a CO.sub.2 absorber.