The present invention provides a metal electrode stabilised by a coating, the coating comprising a sulfur containing moiety in its molecular structure. The coating may also include a hydrophilic group and a spacer between the sulfur containing moiety and the hydrophilic group. Preferably, the sulfur containing moiety is selected from the group comprising thiol, disulfide and SOx, and the hydrophilic group is selected from the group comprising hydroxyl, amine, carboxyl, carbonyl, oligo (ethylene oxide) chain, and zwitterionic species. Compounds useful in the present invention include 2-mercaptoethanol, 2-mercaptoethylamine, 3-mercaptopropionic acid, thiophene, 4-carboxythiophene, cysteine, homocysteine, and cystine.