Protonic ceramic cells (PCCs) are recognized as a promising energy conversion technology for green hydrogen and electricity production owing to their high efficiency, all-solid-state structure, and exceptional reversibility. However, the inadequate mechanical strength of proton-conducting electrolytes remains a critical challenge hindering the widespread application of PCCs. In this study, a cation regulation strategy is employed to enhance the electrolyte mechanical strength by doping silicon (Si) at the B-site of the conventional proton-conducting material BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3 − δ (BZCYYb). The optimized Ba(Zr 0.1 Ce 0.7 Y 0.1 Yb 0.1 ) 0.99 Si 0.01 O 3 − δ (BZCYYbSi) demonstrates significantly improved grain boundary conductivity, structural stability, and mechanical strength, achieving a hardness of 3.11 GPa—1.5 times greater than that of pristine BZCYYb (1.14 GPa). The PCC incorporating a thin-film BZCYYbSi electrolyte exhibits a peak power density of 1.179 W cm −2 at 600 °C in fuel cell mode and an electrolysis current density of 1.591 A cm −2 at 1.3 V/600 °C, outperforming the BZCYYb-based counterpart (0.994 W cm −2 and 1.244 A cm −2 ). Additionally, the BZCYYbSi-based PCC maintains a stable operation for over 370 h at 550 °C in a continuous discharge and electrolysis situation. This work provides new insights for the design and fabrication of mechanically strengthened and high-performance electrolytes for low-temperature PCCs.
Shujun Peng,Song Lei,Sisi Wen,Guowei Weng,Kun Ouyang,Zongjie Yin,Jian Xue,Haihui Wang
Proton conducting solid oxide fuel cells (H–SOFCs) have attracted much interest for their various advantages. BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ (BZCYYb) displays both good proton conductivity and stability among all of the barium zirconate-cerate oxides such as BaZr 0.1 Ce 0.7 Y 0.2 O 3-δ (BZCY) with proton conducting. In this study, an Fe and Ta co-doped perovskite-type oxide with the composition of BaCo 0.7 Fe 0.2 Ta 0.1 O 3-δ (BCFT) is synthesized by the solid state reaction (SSR) method and studied as a high-performance cathode for H–SOFCs operated between 650 and 800 °C. The BCFT is chemically compatible with BZCYYb electrolyte, even co-sintering at 1000 °C for 10 h. The activating energy (Ea) of electrical conductivity for the BCFT sample is only 0.038 eV. The BCFT demonstrates superior oxygen reduction reaction (ORR) kinetics than that of BaCo 0.7 Fe 0.2 Nb 0.1 O 3-δ (BCFN), when the Nb is completely substituted by Ta. The Ea of the polarization resistance (Rp) for BCFT is 0.911 eV, which is 0.11 eV lower than that of BCFN. The peak power density (PPD) of the anode-supported H–SOFC using BCFT is 1.65 W cm −2 and the Rp is 0.01 Ω cm 2 at 800 °C. Therefore, the BCFT is a promising cathode for H–SOFCs based on BZCYYb electrolyte.
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.
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