Praseodymium nickelate (Pr₂NiO₄) is an active oxygen electrode in solid oxide fuel cells, however it undergoes a phase transition at elevated temperatures or under an electrochemical operation to form PrO_x and higher ordered nickelate phase. In this work, we attempt to suppress the phase transition by adding Pr₆O₁₁ to Pr₂NiO₄ to form a composite. Two approaches are adopted: the first is to infiltrate Pr₂NiO₄ with Pr₆O₁₁ and the second one is to use a mixture of Pr₂NiO₄ and Pr₆O₁₁ powders. In case or (Pr,Nd)₂NiO₄ is used, the 2^nd oxide phase is subsequently changed to (Pr,Nd)₂O₃. Anode supported single cells are used to measure the performance of the composite electrode. XRD is used to analyze the cathode structure and does show the suppression on phase evolution. In addition, the infiltrated cells show a high initial performance and the performance is stable during the 100-hours accelerated measurement.