Shaping triple-conducting semiconductor BaCo0.4Fe0.4Zr0.1Y0.1O3-δ into an electrolyte for low-temperature solid oxide fuel cells

• Published in: Nature communications Vol. 10; no. 1; p. 1707
• Main Authors: Xia, Chen, Mi, Youquan, Wang, Baoyuan, Lin, Bin, Chen, Gang, Zhu, Bin
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 12.04.2019; Nature Publishing Group; Nature Portfolio
• Subjects: 147/135; 147/143; 639/301/299/161; 639/301/299/893; Conduction; Conductivity; Electrodes; Electrolytes; Electrolytic cells; Fuel cells; Fuel technology; Heterojunctions; Heterostructures; Humanities and Social Sciences; Hydrogen; Ion currents; Ions; Low temperature; Molten salt electrolytes; multidisciplinary; P-n junctions; Perovskites; Science; Science (multidisciplinary); Solid electrolytes; Solid oxide fuel cells; Temperature effects; Zinc oxide
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-019-09532-z

Interest in low-temperature operation of solid oxide fuel cells is growing. Recent advances in perovskite phases have resulted in an efficient H + /O 2- /e - triple-conducting electrode BaCo 0.4 Fe 0.4 Zr 0.1 Y 0.1 O 3-δ for low-temperature fuel cells. Here, we further develop BaCo 0.4 Fe 0.4 Zr 0.1 Y 0.1 O 3-δ for electrolyte applications by taking advantage of its high ionic conduction while suppressing its electronic conduction through constructing a BaCo 0.4 Fe 0.4 Zr 0.1 Y 0.1 O 3-δ -ZnO p-n heterostructure. With this approach, it has been demonstrated that BaCo 0.4 Fe 0.4 Zr 0.1 Y 0.1 O 3-δ can be applied in a fuel cell with good electrolyte functionality, achieving attractive ionic conductivity and cell performance. Further investigation confirms the hybrid H + /O 2- conducting capability of BaCo 0.4 Fe 0.4 Zr 0.1 Y 0.1 O 3-δ -ZnO. An energy band alignment mechanism based on a p-n heterojunction is proposed to explain the suppression of electronic conductivity and promotion of ionic conductivity in the heterostructure. Our findings demonstrate that BaCo 0.4 Fe 0.4 Zr 0.1 Y 0.1 O 3-δ is not only a good electrode but also a highly promising electrolyte. The approach reveals insight for developing advanced low-temperature solid oxide fuel cell electrolytes. Solid oxide fuel cells enable efficient electricity generation at high temperatures. Here the authors incorporate a mixed ion-electron semiconductor into another semiconductor to form a p-n junction to suppress electron conduction and enhance ion conduction, leading to a low-temperature electrolyte.