Ion dynamics in the pseudocapacitive reaction of hydrous ruthenium oxide. Effect of the temperature pre-treatment

► Annealed hydrous ruthenium oxide on gold support achieves capacitances higher than 1500 F g−1. ► Two faradaic and double layer charging processes simultaneously take place during charging/discharging reactions. ► Dissociative adsorption of water proceeds with the incorporation of oxygen into the structure. ► Simultaneous proton-electron exchange reaction is favored in acidic media.