JOURNAL OF POWER SOURCES
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2023
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IF 9.2
Jiaming Yang,Jun Zhou,Zhengrong Liu,Yueyue Sun,Chaofan Yin,Kaiteng Wang,Ruhuan Li,Zilin Zhou,Kai Wu
In-situ exsolution technique, as an efficient and controllable strategy of surface modification, has been extensively applied in reversible solid oxide cells (RSOCs). Here, we demonstrate La x Sr x Ti 0.9 Ni 0.1 O 3-δ fiber decorated by exsolved Ni nanoparticles and highlight the impacts of A-site deficiency on Ni exsolution and electrochemical performance of RSOCs. The La 0.4 Sr 0.4 Ti 0.9 Ni 0.1 O 3 (A/B = 0.8) fibrous fuel electrode decorated by Ni nanoparticles with moderate Ni exsolution displays optimum electrochemical performance at 800 °C, achieving ∼540 mW cm −2 in SOFC mode and −0.742/0.385 A cm −2 under 1.3/0.7 V in RSOC mode. In contrast, high A-site deficiency (A/B < 0.8) allows heterogeneous phases (NiTiO 3 ) and excessive Ni exsolution along with alterations of fibrous morphology, leading to slow gas diffusion, sluggish catalysis, and Ni agglomeration. The distribution of relaxation time (DRT) results show that the rate-limiting steps in symmetrical cells are gas diffusion, hydrogen adsorption, and dissociation, accounting for over 89% of the total R P . Ni-equilibrium model based on X-ray Rietveld refinement calculates the degree of exsolution with various A-site deficiency, revealing NiTiO 3 is the key factor of excessive exsolution. Our work of high A-site deficiency exemplified here may serve in the design and nanoengineering of fibrous ABO 3 perovskite oxides for RSOCs.
研究领域:
材料科学
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能源工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
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2022
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IF 4.598
Na Xu,Longjiao Yu,Jiyuan Zhang,Jingdong Feng,Lina Zhao
The development of efficient non-noble metal electrocatalysts for the oxygen reduction reaction (ORR) can aid the commercialization of fuel cells and metal-air batteries. Here, we developed a series of La 0.4 Sr 0.6 Co 0.7 Fe 0.2 Nb 0.1 O 3-δ (LSCFN) perovskites by engineering A-site deficiency to enhance their electrocatalytic activity for ORR in alkaline solutions. We found that LSCFN-0.90 with the highest amount of vacant A-sites has a highly oxidative oxygen species (O 2 2− /O − ) and an appropriate Co oxidation state - is a much better ORR catalyst in alkaline solutions compared to those with less vacant A-sites. The enhanced ORR kinetics enabled their use as the cathode catalyst in aluminum-air batteries, which also revealed better electrochemical performances for the catalyst with the highest A-site deficiency. Overall, the results demonstrate that an appropriate A-site cation deficiency in perovskites can enhance the ORR electrocatalytic activity.
研究领域:
材料科学
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电化学
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能源技术
✓ 已验证
DOI
高影响因子
ACS Applied Energy Materials
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2022
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IF 6.959
Limin Liu,Mengxin Wu,Xiaoliang Zhou,Hanyu Chen,Xinyuan Qian,Zhou Wang,Feifan He,Yang Sheng,Jiaqi Qian,Lu Pan
Solid oxide fuel cells (SOFC) with symmetric configuration have received widespread attention for their potential immunity toward resisting coking and sulfur poisoning. A key requirement for electrodes in the development of symmetric solid oxide fuel cells is the high electrocatalytic activity in both oxidizing and reducing atmospheres. Herein we report a facile method to improve the electrochemical performance of La0.3Sr0.7Ti0.3Fe0.7O3-δ- (LSTF-) based perovskite electrode material by introducing the deficiency in the A-site. X-ray diffraction (XRD) results demonstrated that A-site deficient LSTF exsolves a small amount of Fe0 metallic particles and layer perovskite Sr2TiO4, which exhibits high electrical conductivity in H2 atmosphere, while at the same time the exsolution is reversible. The polarization resistances (Rp) of (La0.3Sr0.7)0.95Ti0.3Fe0.7O3-δ (LSTF-5%) are 0.032 and 0.110 Ω cm2 in air and wet H2 (containing 3% H2O), respectively, at 800 °C. The power density of the electrolyte-supported SSOFCs with LSTF-5% as symmetrical electrode reaches up to 431.8 mW cm–2 at 800 °C in wet H2/air. And the LSTF-5% symmetrical cell also exhibits excellent electrochemical performance and high stability for electrochemically reducing pure CO2. Therefore, LSTF-5% perovskite can act as an excellent electrode material in a symmetrical SOFC. The results in this paper also indicate that an appropriate amount of A-site deficiency on LSTF perovskite can lead to an increase in oxygen vacancy concentration and better electrochemical performance.
研究领域:
材料科学
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能源科学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2024
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IF 8.1
Zhenqiang Yu,Yihao Xu,Rong Guo,Jinming Zeng,Zheng Xie,Menglian Zhang,Yi Fang,Xiaopeng Qi,Zhe Lü,Huan Li
The development of highly active and durable cathode is a pivotal factor for fully unlocking the commercial potential of solid oxide fuel cells (SOFCs). Herein, the La 0.5 Ba 0.5-x FeO 3-δ ( x = 0, 0.01) oxides were prepared, and the impacts of A-site deficiency were studied in detail. The introduction of A-site defects leads to lattice contraction of the cubic perovskite structure and lower thermal expansion coefficient. Introducing A-site deficiency into La 0.5 Ba 0.5 FeO 3-δ yields more oxygen vacancies and higher electrical conductivity. Compared with La 0.5 Ba 0.5 FeO 3-δ material, the La 0.5 Ba 0.49 FeO 3-δ achieves the lowest polarization resistance of 0.089 Ω cm 2 and the maximum power density of 464 mW cm 2 at 750 °C, while performing exceptional stability for a duration of 100 h. Moreover, the oxygen partial pressure dependence and the distributions of relaxation times analyses effectively identify the rate-limiting steps of the overall oxygen reduction process. These results indicate that the La 0.5 Ba 0.49 FeO 3-δ oxide is a high-performance cathode catalyst material for SOFCs.
研究领域:
材料科学
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能源科学
✓ 已验证
产品关联
DOI
高影响因子
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