Improving materials for energy conversion and storage devices is deeply connected with an optimization of the surfaces of these materials. Surface modification has therefore emerged as a very promising strategy on the way to enhance modern energy technologies. This study shows that surface modification with ultra-thin oxide layers allows for a systematic tailoring of surface properties, in particular of the surface dipole and the work function, and it introduces the ionic potential of surface cations as a readily accessible descriptor for these effects. The combination of X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) illustrates that basic oxides with a lower ionic potential than the host material induce a positive surface charge and reduce the work function of a mixed conducting host material and vice versa. The emerging surface dipoles are caused by changes in the energy landscape, leading to redistribution of electronic charge density and/or a geometric reorientation of the surface. As a proof of concept that this strategy is widely applicable to tailor surface properties, we examined the effect of ultra-thin decoration layers on the oxygen exchange kinetics of pristine thin films of structurally and chemically different mixed conducting oxides in very clean conditions by means of in-situ impedance spectroscopy during pulsed laser deposition (i-PLD). The extended study confirms that basic decorations with a reduced surface work function lead to a substantial acceleration of the oxygen exchange on a material's surface. Computational results suggest that the underlying mechanism of the kinetic improvement relies on a modification of the energetics of charged O2 adsorbates and substantiate their importance for the oxygen exchange reaction.