Preparation and Electrochemical Performance of Ni Doped Ba_0.5Sr_0.5(Co_0.8Fe_0.2)_1-xNi_xO_3-δ Cathodes for Proton Ceramic Fuel Cells

The electrochemical performance of conventional mixed ionic-electronic conducting oxides Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ(BSCF) in proton ceramic fuel cells (PCFCs) has been improved by using nickel doping strategy. A series of Ba_0.5Sr_0.5(Co_0.8Fe_0.2)_1-xNi_xO_3-δ samples were synthesized by using sol-gel method. Chemical compatibility and stability between the Ba_0.5Sr_0.5(Co_0.8Fe_0.2)_0.9Ni_0.1O_3-δ (BSCFN10) cathode and the electrolyte BaZr_0.1Ce_0.7Y_0.2O_3-δ (BZCY) were studied, which was used in the PCFCs. Catalytic activity of the electrodes was evaluated by constructing a symmetric cell. It is showed that the BSCFN10 cathode has superior catalytic activity than BSCF. Peak power density of the BSCFN10 cathode was enhanced from 380 mW·cm^-2 to 503 mW·cm^-2 and the polarization impedance was reduced from 0.21 Ω·cm² to 0.12 Ω·cm², as compared with the undoped BSCF within a hydrogen atmosphere containing 3% water vapor at 700 ℃. In addition, the BSCFN10 electrode exhibited excellent operating stability at a current density of 0.4 A·cm^-2, showcasing its potential for application in PCFCs.