Photo-assisted synthesis of protonated oxides for fuel cells.

The absence of intrinsic protons in proton-conducting oxides (PCO) is a significant challenge that limits the proton conductivity of proton-conducting perovskites, such as Y-doped BaMO (M = Zr, Ce), in proton ceramic fuel cells exhibit low conductivity (10 to 10 S cm at 600 °C). Herein, we introduce a photo-assisted synthesis method for incorporating protons into Al-doped ceria (AlCeO, x = 0.2; M-ACO), leveraging the open cubic fluorite structure and photo-activated radical reactions. Specifically, photon-generated hydroxyl reactive and superoxide ( ) Radicals are generated and interact with the ACO crystal lattice, facilitating proton incorporation and resulting in the synthesis of native-proton-type PCO. This process results in a protonated (H-ACO) with a high proton conductivity of 0.14 S cm and exceptional power density of 922 mW cm at 500 °C. This versatile synthesis methodology offers broader development of advanced PCO for energy-related applications.