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Attempted preparation of La 0.5 Ba 0.5 MnO 3− δ leading to an in-situ formation of manganate nanocomposites as a cathode for proton-conducting solid oxide fuel cells

2023; Springer Science+Business Media; Volume: 12; Issue: 6 Linguagem: Inglês

10.26599/jac.2023.9220748

2227-8508

Rui Zhou, Yanru Yin, Hailu Dai, Xuan Yang, Yueyuan Gu, Lei Bi,

Electronic and Structural Properties of Oxides

A La 0.5 Ba 0.5 MnO 3-δ oxide was prepared using the sol-gel technique. Instead of a pure phase, La 0.5 Ba 0.5 MnO 3-δ was discovered to be a combination of La 0. 7 Ba 0. 3 MnO 3-δ and BaMnO 3 . The in-situ production of La 0. 7 Ba 0. 3 MnO 3-δ +BaMnO 3 nanocomposites enhanced oxygen vacancy formation compared to single-phase La 0. 7 Ba 0. 3 MnO 3-δ - or BaMnO 3 , providing potential benefits as a cathode for fuel cells. Subsequently, La 0. 7 Ba 0. 3 MnO 3-δ -+BaMnO 3 nanocomposites were utilized as the cathode for proton-conducting solid oxide fuel cells (H-SOFCs), which significantly improved cell performance. At 700 o C, an H-SOFC with a La 0. 7 Ba 0. 3 MnO 3-δ + BaMnO 3 nanocomposite cathode achieved the highest power density yet recorded for H-SOFCs with manganate cathodes: 1504 mW cm -2 . This performance was much greater than the single-phase La 0. 7 Ba 0. 3 MnO 3-δ or BaMnO 3 cathode cells. In addition, the cell demonstrated excellent working stability. First-principles calculations indicated that the La 0. 7 Ba 0. 3 MnO 3-δ /BaMnO 3 interface was crucial for the enhanced cathode performance. The oxygen reduction reaction (ORR) free energy barrier was significantly lower at the La 0. 7 Ba 0. 3 MnO 3-δ /BaMnO 3 interface than at the La 0. 7 Ba 0. 3 MnO 3-δ or BaMnO 3 surfaces, which explained the origins of the high performance and gave a guide for the construction of novel cathodes for H-SOFCs.