Zeyun Wu,Yiyang Zhang,Zuoqing Liu,Haorui Ma,Xing Jin,Guangming Yang,Yixiang Shi,Zongping Shao,Shuiqing Li
Perovskite-type proton-conducting materials, such as BaCe0.7Zr0.1Y0.1Yb0.1O3−δ (BCZYYb), are very attractive for the next-generation equipment of electrochemical energy conversion and storage owing to their excellent conductivity in the intermediate-temperature range (300–750 °C), as well as good thermo-chemical stability, coking resistance, and sulfur tolerance. However, the lack of a reliable and cost-effective synthesis method for such multi-component co-doping oxides limits their large-scale application. In this study, for the first time, we successfully synthesize BCZYYb electrolyte nanopowders by using a rapid, scalable flame-based gas-phase synthesis method with two different barium precursors Ba(NO3)2 and Ba(CH3COO)2, named as BCZYYb (N) and BCZYYb (CA). The as-synthesized nanoparticles exhibit good crystallinity of the pure orthorhombic perovskite BCZYYb phase. BCZYYb (CA) shows more uniform doping with the element ratio of 1:0.74:0.12:0.08:0.1, which is very close to the theoretical value. The shrinkage and surface SEM (scanning electron microscope) results indicate that the flame-made powders have superior sinterability compared to the sol–gel-made powders because of the smaller primary particle size (∼20 nm). Electrochemical impedance spectroscopy tests show that BCZYYb (CA) sintered at 1450 °C has the highest protonic conductivity of 1.31 × 10–2 S cm–1 in wet H2 when operating at 600 °C and still maintains a high-level conductivity of 1.19 × 10–2 S cm–1 even when the sintering temperature is reduced to 1350 °C, which is mainly attributed to uniform doping and good sinterability. The activation energy for the conductivity of BCZYYb (CA) is also significantly lower than that of conventional electrolytes, which suggests much better conductivity in the intermediate (∼600 °C) and even lower operating temperature. The excellent conductivity performance combined with the high-throughput production capability makes the swirling spray flame a promising synthesis method for promoting the BCZYYb electrolytes from lab to industrial-scale solid oxide fuel cells.
Ammonia-fueled protonic ceramic fuel cells (PCFCs) are emerging as promising alternatives to H 2 -fueled PCFCs, offering advantages such as higher energy density and enhanced safety. However, their widespread application is impeded by challenges, including insufficient catalytic activity towards ammonia and limited stability of the anode structure. Herein, we report a rational design for Ni 97 Co 3 -BaCe 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 3− δ (BCZYYb) cermet anodes, aimed at enhancing both catalytic activity and durability for ammonia utilization. The cell featuring the Ni 97 Co 3 -BCZYYb anode leverage the synergistic interaction between Ni and Co to enhance ammonia adsorption and nitrogen desorption, resulting in a remarkable 67.8 % increase in power density when operating with NH 3 at 600 °C. Notably, upon switching the fuel from H 2 to NH 3 , this achieves an unprecedented power retention of 87.2 % at 700 °C, representing one of the highest values recorded for ammonia-fueled PCFCs, while most ammonia-fueled cells exhibit power retention in the range of only 60–80 %. Furthermore, the cell with Ni 97 Co 3 -BCZYYb cermet anode demonstrates exceptional durability, stable operation over 30 h at 650 °C under NH 3 with no degradation observed. This longevity is attributed to the excellent sintering resistance of the NiCo alloy, highlighting the potential of the Ni 97 Co 3 -BCZYYb cermet anode for long-term applications. This work provides an effective strategy for designing highly active and durable anodes for ammonia-fueled PCFCs.
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