Effects of transition metal ion dopants on the performance of Ca2.9Bi0.1Co4O9−δ cathode

► Ten transition metal ions were doped into Ca2.9Bi0.1Co4O9−δ cathode. ► Cu doped Ca2.9Bi0.1Co4O9−δ shows the highest electrical conductivity. ► Cu doped Ca2.9Bi0.1Co4O9−δ shows the highest peak power density at 800 °C.