In situ growth of nanoparticles in A-site deficient ferrite perovskite as an advanced electrode for symmetrical solid oxide fuel cells

Perovskites decorated with catalytically active nanoparticles show promising potential in power generation and energy conversion. Here, with the aim of developing symmetrical solid oxide fuel cells (SSOFCs) possessing high performance, an ingenious approach of in situ exsolution of metallic Ru nanoparticles under SSOFC operating condition is proposed. In this study, a novel perovskite oxide with A-site deficiency Sm_0.70Sr_0.20Fe_0.80Ti_0·15Ru_0·05O_3−δ (SSFTR7020) is meticulously designed and successfully synthesized. At 800 °C, the polarization resistance (R_p) of SSFTR7020 cathode is only 0.13 Ω cm², since the adidtionally formed oxygen vacancies contribute to the oxygen reduction reaction. Moreover, it is found that numerous metallic Ru nanoparticles are exsolved from SSFTR7020 perovskite support upon reduction, while no partilcle can be observed for stoichiometric SSFTR perovskite. This is because the artificially introduced deficiency can make exsolutsion become more dynamic. The maximum power output of symmetrical cell SSFTR7020|Sm_0.2Ce_0·8O_1.9 (SDC)|SSFTR7020 reaches 476 mW cm⁻² after operation ~96 h at 800 °C in humidified hydrogen.