Spinel Ni-doped LiMn2O4 cathode material with high oxygen reduction catalytic performance for low temperature solid ceramic fuel cells

In this work, Ni-doped LiMn2O4 spinel oxides were studied as the cathode materials of low temperature proton ceramic fuel cell. Increasing the content of doping Ni to 0.5, the calculated active energy of the polarization process of the cell decreased from 0.62 to 0.49 eV. The cell performance increased with the Ni doping of LiMn2O4 cathode, and the optimal power density reached to 547 mW cm-2 at 550 degrees C with a low polar resistance of 0.42 omega cm2 for LiNi0.5Mn1.5O4. Ni partially replacing Mn at the B site could increase the content of Mn4+, resulting in the increase of oxygen vacancy content to maintain the charge balance, which is beneficial to the oxygen reduction reaction. These results demonstrate that spinel oxide could be a promising cathode material with highly oxygen reduction activity for advanced low temperature solid ceramic fuel cells.