H₂ treatment benefit stable operation for ceramic fuel cells with NFMNa electrolyte at lower temperature

MS-XN-33S-Ternary sodium nickel-ferric manganate layered oxide (NFMNa), a commercialized electrode material for sodium battery, has been used as electrolyte in low-temperature ceramic fuel cells (LT-CFCs) and has attained stable operation for 110 h at 500 °C. In order to reach stable operation of fuel cells at lower temperatures, H₂ treated NFMNa (H-NFMNa) is studied. We find that the Ni (Fe, Mn)-O bond length in the H-NFMNa is shorter than that in NFMNa, while the Na−O bond length in H-NFMNa is longer than that in NFMNa. And the content of polycrystalline Na₂CO₃ increases in H-NFMNa. Ceramic fuel cells with H-NFMNa electrolyte have ion conductivity of 0.092 S cm⁻¹ and peak power density of 523 mW cm⁻² at 500 °C. Hydrogen and oxygen concentration cells indicate that H-NFMNa material can only conduct protons in 400–520 °C, while can simultaneously conduct proton and oxygen ion in 540–600 °C. Finally, the fuel cell device using NFMNa electrolyte and BaZr_0.1Ce_0.7Y_0.2O_3-δ (BZCY) buffer layer obtain stable operation for 182 h at 490 °C. This result is beneficial for the development of LT-CFCs electrolyte materials and lithium/sodium batteries electrode materials.