Solid oxide fuel and electrolyzer cells (SOFC and SOEC) are considered key for a sustainable energy system. Symmetric solid oxide cells will reduce costs of this technology but require redox stable electrodes. Ni-doped Sr(Ti,Fe)O3-d, in particular Sr0.93Ti0.3Fe0.63Ni0.07O3-d (STFN) is a suitable perovskite capable to work well as anode and cathode. This synchrotron operando study on model cells reveals how electrode polarization also affects exsolution in relation to temperature and chemical potential of the atmosphere in SOFC/SOEC cycles. We show that tuning exsolution is possible if the chemical potential of the atmosphere and electrode polarization EWE compete, i.e. in H2/SOFC or O2/SOFC modes.