Ionic conducting properties and fuel cell performance developed by band structures

: The layer-structure transition-metal oxides have good triple H+ / O2−/e− charge transport which can promote redox reactions and enhance fuel cell performance. This work has developed ionic transport property based on the layer-structure LiCoO2 (LCO) by tuning the energy band structure with Mg doping also applied for the electrolyte in high-performance lowtemperature solid oxide fuel cells (LT-SOFCs). Mg-doped LiCoO2 exhibited a hexagonal-layered structure with the R3m space group. By doping LiCoO2, its band gap was reduced from 2.65 to 2.24 eV. Electrochemical impedance analysis revealed that Mg-doped LCO (LMCO) significantly reduces the polarization loss (charge-transfer resistance) from 0.85 to 0.5 Ω cm2 at 600 °C; the power output of the fuel cell devices improved from 0.5 to 0.7 W/cm2 , resulting also in better operation durability. Various characterizations on structural and electrochemical properties were conducted. The mechanism was further discussed in relation with the band structure