For protonic ceramic fuel cells, it is key to develop material with high intrinsic activity for oxygen activation and bulk proton conductivity enabling water formation at entire electrode surface. However, a higher water content which benefitting for the increasing proton conductivity will not only dilute the oxygen in the gas, but also suppress the O₂ adsorption on the electrode surface. Herein, a new electrode design concept is proposed, that may overcome this dilemma. By introducing a second phase with high-hydrating capability into a conventional cobalt-free perovskite to form a unique nanocomposite electrode, high proton conductivity/concentration can be reached at low water content in atmosphere. In addition, the hydronation creates additional fast proton transport channel along the two-phase interface. As a result, high protonic conductivity is reached, leading to a new breakthrough in performance for proton ceramic fuel cells and electrolysis cells devices among available air electrodes.