摘要
Designing high-performance cathodes is crucial for proton-conducting solid oxide fuel cells(H-SOFCs),as the cathode heavily influences cell performance.Although manganate cathodes exhibit superior stability and thermal compatibility,their poor cathode performance at intermediate temperatures renders them unsuitable for H-SOFC applications.To address this issue,Sc is utilized as a dopant to modify the traditional La_(0.5)Sr_(0.5)MnO_(3) cathode at the La site.Although the solubility of Sc at the La site is restricted to 2.5%,this modest quantity of Sc doping can improve the material's oxygen and proton transport capabilities,hence improving cathode and fuel cell performance.Furthermore,when the doping concentration exceeds 2.5%,the secondary phase ScMnO3 forms in situ,resulting in La_(0.475)Sc_(0.025)Sr_(0.5)MnO_(3)(LScSM)+ScMnO_(3) nanocomposites.Although the secondary phase is often considered undesirable,the high protonation capacity of ScMnO_(3) can compensate for the low proton diffusion ability of LScSM.These two phases complement each other to provide high-performance cathodes.The nominal La_(0.4)Sc_(0.1)Sr_(0.5)MnO_(3) is the optimal composition,which takes advantage of the excellent electronic conductivity and fast oxygen diffusion rates of LScSM,as well as the good proton diffusion capacity of ScMnO_(3),to produce a high fuel cell output of 1529 mW·cm^(−2) at 700°C.Furthermore,the fuel cell exhibited good operational stability under working conditions,indicating that La_(0.4)Sc_(0.1)Sr_(0.5)MnO_(3) is a viable cathode choice for H-SOFCs.
基金
supported by the National Natural Science Foundation of China(Grant Nos.52302314,52272216,and 12274361).
作者简介
Corresponding author:Lei Bi,E-mail:lei.bi@usc.edu.cn,bilei81@gmail.com;Corresponding author:Qinfang Zhang,E-mail:qfangzhang@ycit.edu.cn。
