Ti-modified MnCo₂O₄ spinel cathodes for proton-conducting solid oxide fuel cells

This work puts forward a Ti-doping strategy to engineer the MnCo₂O₄ (MCO) spinel oxide as a cathode for in proton-conducting solid oxide fuel cells (H-SOFCs). The resulting MnCo_1.8Ti_0.2O₄ (Ti-MCO) oxide exhibits favorable structural stability under high-temperature conditions, with Ti incorporation leading to an elevated oxygen vacancy concentration. Ti-MCO also demonstrates improved oxygen diffusivity and surface exchange capability relative to its Ti-free counterpart. Consequently, H-SOFCs equipped with the Ti-MCO cathode deliver enhanced performance compared to those with the MCO cathode. At 700 °C, the Ti-MCO cell achieves a peak power density of 1530 mW cm⁻², substantially surpassing the 829 mW cm⁻² recorded for the MCO cell. Moreover, the Ti-MCO cell demonstrates robust operational stability under working conditions, maintaining consistent performance for over 140 h with no noticeable degradation. This study indicates that Ti-MCO is an effective cathode material for H-SOFCs with high performance and good stability.