Electrochemical evaluation of Pr1.85M0.15NiO4+x (M=Ba, Sr, Ca) cathodes for protonic ceramic fuel cells

Pr 1.85 M 0.15 NiO 4+x (M represents Ba, Sr, or Ca) materials were prepared and evaluated as cathodes for protonic ceramic fuel cells (PCFCs). Compared with the Sr and Ba doping methods, the Ca -doping approach slightly enhanced the generation of interstitial oxygen and the surface catalytic activity in Pr 2 NiO 4 . Furthermore, Cadoping decreases the distance between O atoms in the lattice compared with the Sr and Ba-doped Pr 2 NiO 4 , facilitating the movement of charge carriers. Consequently, PCFCs employing Ca -doped Pr 2 NiO 4 cathodes achieve a much greater power density of 1279 mW cm -2 at 700 degrees C compared to fuel cells employing Sr -doped or Badoped Pr 2 NiO 4 cathodes. Furthermore, a PCFC employing a Ca -doped Pr 2 NiO 4 cathode exhibited excellent longterm stability under working conditions and operated continuously for over 280 h without any discernible deterioration. These results indicate that the Ca -doped Pr 2 NiO 4 cathode is a stable and effective candidate for PCFCs.