TiO2-induced electronic change in traditional La0.5Sr0.5MnO3−δ cathode allows high performance of proton-conducting solid oxide fuel cells

Sr-doped LaMnO₃, as one of the most successful cathodes for solid oxide fuel cells (SOFCs), can effectively function at high temperatures. However, its cathode kinetics considerably decreases with decreasing temperature, rendering it unsuitable for SOFCs operating at intermediate temperatures. In this study, La_0.5Sr_0.5MnO_3−δ(LSM) is coated with TiO₂ to create the LSM + TiO₂ cathode. TiO₂ is shown to modify the electronic structure at the LSM/TiO₂ interface, allowing for charge accumulation for the O atoms at the interface. The activated O atoms enhance the formation of oxygen vacancies, which benefit the oxygen diffusion ability. Using LSM + TiO₂ as a cathode for proton-conducting SOFCs (H-SOFCs) operating at intermediate temperatures, the corresponding fuel cell demonstrated enhanced cell output performance compared with cells employing solely LSM or TiO₂ cathodes, exhibiting the synergistic effect of combining LSM and TiO₂. Additionally, the LSM + TiO₂ cells achieved a power output of 1118 mWcm⁻² at 700°C, the highest yet reported value for H-SOFCs with LSM cathodes. LSM + TiO₂ was demonstrated to be stable against CO₂ and steam, allowing for steady functioning of the cell under working conditions, thereby resolving the problem of LSM’s poor performance in H-SOFCs while retaining remarkable stability.