IONICS
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2021
·Vol. 27
·期 9
·3951-3965
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IF 2.817
Meng Yu,Zhang Qing,Chen Zhijian,Chen Xu,Zhou Jing,Zhu Xiaofei,Wang Ning,Zhou Defeng
The sol-gel method was adopted to synthesize novel cobalt and strontium-free Pr 0.5 Ba 0.5 Fe 1- x Ni x O 3-δ ( x = 0 and 0.2, abbreviated as PBF and PBFN) perovskite oxides. It was aimed to discuss the influence of B-site Ni substitution on structure and electrochemical properties of Pr 0.5 Ba 0.5 FeO 3-δ . The results indicated that PBF-based oxides were both cubic perovskite structure. Ni atoms were successfully doped into the B sites of PBF, resulting in lattice shrinkage. Ni doping could enhance the oxygen reduction activity by increasing the surface oxygen content and the release of lattice oxygen to increase oxygen vacancies. At 700 °C, the cathodic polarization resistance of PBFN (0.0726 Ω·cm 2 ) was lower than PBF (0.122 Ω·cm 2 ), and the maximum power density (PPD) of PBFN (528.79 mW·cm −2 ) was higher than PBF (259.65 mW·cm −2 ). After 80 h polarization, the open-circuit voltage did not change significantly. Therefore, PBFN has the potential to be more suitable cathode material of IT-SOFCs. Graphical abstract
研究领域:
材料科学
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能源科学
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DOI
高影响因子
ELECTROCHEMISTRY COMMUNICATIONS
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2022
·
IF 5.443
Ziwei Dong,Tian Xia,Qiang Li,Jingping Wang,Shuang Li,Liping Sun,Lihua Huo,Hui Zhao
Highly active cathode materials are crucial to accelerating the commercialization of intermediate-temperature solid oxide fuel cells (IT-SOFCs). Herein, Sr-doped Pr 0.94 Ba 1- x Sr x Co 2 O 5+ δ (PBS x CO) perovskite oxides are evaluated by experimental and theoretical studies. The phase transformation from tetragonal layered double perovskite to cubic simple perovskite can be identified with increasing the Sr fraction. Benefiting from enhanced electrical conductivity and oxygen surface rate, the PBS x CO catalysts deliver excellent electrochemical performance, as evidenced by symmetrical and completed cells test. Among all compositions, the Pr 0.94 Ba 0.7 Sr 0.3 Co 2 O 5+ δ (PBS0.3CO) cathode has the lowest polarization resistance ( R p ) of 0.031 Ω cm 2 at 700 °C. The PBS0.3CO cathode-based fuel cell produces a peak power density of 1077 mW cm −2 , along with a steady operating for 130 h at 700 °C. From the density functional theoretical (DFT) calculations, it is discovered that stronger Co 3d-O 2p hybridization is recognized in the Sr substituting model compared with undoped one. Furthermore, the decreased free energy for oxygen adsorption may facilitate the oxygen reduction reaction (ORR) kinetics. These findings highlight the origin of optimal ORR activity induced by A-site alkaline earth doping in the perovskite catalysts, endowing the rational design of oxide catalysts.
研究领域:
材料科学
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能源科学
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DOI
高影响因子
MOLECULES
·
2024
·Vol. 29
·期 22
·5299
·
IF 4.2
Liangmei Xue,Songbo Li,Shengli An,Ning Li,Huipu Ma,Mengxin Li
Double perovskite oxides with mixed ionic and electronic conductors (MIECs) have been widely investigated as cathode materials for solid oxide fuel cells (SOFCs). Classical Fe-based double perovskites, due to their inherent low electronic and oxygen ionic conductivity, usually exhibit poor electrocatalytic activity. The existence of various valence states of B-site ions modifies the material’s catalytic activity, indicating the possibility of the partial substitution of Fe by higher-valence ions. LaBaFe2−xMoxO5+δ(x= 0, 0.03, 0.05, 0.07, 0.1, LBFMx) is used as intermediate-temperature solid oxide fuel cell (IT-SOFC) cathode materials. At a doping concentration above 0.1, the Mo substitution enhanced the cell volume, and the lattice expansion caused the formation of the impurity phase, BaMoO4. Compared with the parent material, Mo doping can regulate the oxygen vacancy concentration and accelerate the oxygen reduction reaction process to improve the electrochemical performance, as well as having a suitable coefficient of thermal expansion and excellent electrode stability. LaBaFe1.9Mo0.1O5+δis a promising cathode material for IT-SOFC, which shows an excellent electrochemical performance, with this being demonstrated by having the lowest polarization resistance value of 0.017 Ω·cm2at 800 °C, and the peak power density (PPD) of anode-supported single-cell LBFM0.1|CGO|NiO+CGO reaching 599 mW·cm−2.
研究领域:
材料科学
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能源科学
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产品关联
DOI
PubMed
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2021
·
IF 19.503
Leyu Shen,Zhihong Du,Yang Zhang,Xu Dong,Hailei Zhao
Medium-entropy perovskites Sr(Fe α Ti β Co γ Mn ζ )O 3- δ (SFTCM) are investigated as potential cathodes for intermediate temperature solid oxide fuel cell (IT-SOFC). The effects of entropy on crystal structure, thermal expansion coefficients (TEC), electrical conductivity, oxygen surface exchange and bulk diffusion coefficients, electrochemical performance, and long-term stability of SFTCM are systematically investigated. High entropy facilitates the diffusion of oxygen ions but hinders the transmission of electrons. The SFTCM with higher entropy shows a lower TEC, displays suppressed strontium surface segregation, and delivers more stable polarization resistance. Although the catalytic activity towards oxygen reduction reaction was slightly reduced, the maximum power density of the LSGM-supported (250 μm) single cell with SrFe 0.25 Ti 0.25 Co 0.25 Mn 0.25 O 3- δ cathode can still reach 0.85 W cm −2 at 800 °C. All these results suggest that the medium-entropy SFTCM perovskites can be promising cathodes materials for IT-SOFC.
研究领域:
材料科学
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能源工程
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DOI
高影响因子
APPLIED SURFACE SCIENCE
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2023
·
IF 6.7
Xuebai Zhang,Yingmin Jin,Yunjian Jiang,Xin Zong,Yumeng Li,Yueping Xiong
The low catalytic activity and poor long-term stability of cathode at intermediate temperatures are one of the bottlenecks hindering the application of solid oxide fuel cells. In this work, the highly active and robust La 0.8 Sr 0.2 Co 0.2 Fe 0.8 O 3-δ (LSCF) nanofibers based composite cathodes with core-shell structure is prepared applying electrospinning combined with sol-gel method. Owing to the favorable oxygen ion transport capability of Gd 0.2 Ce 0.8 O 1.9-δ (GDC) nanoparticle coating layer, the GDC coated LSCF nanorods composite cathode with GDC:LSCF mass ratio of 0.51:1 obtains the optimal electrochemical performance, reaching a polarization impedance of 0.03 Ω cm 2 at 800 °C. Meanwhile, the composite cathode exhibits no obvious degradation for constant operating 200 h. Remarkably, XPS and Raman characterizations imply that the applying of GDC coating inhibits the formation of SrO and SrCrO 4 during the long-term operating in Cr containing atmosphere, thereby endowing the higher long-term operation stability and Cr poisoning tolerance to LSCF based cathode.
研究领域:
材料科学
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能源技术
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产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Qin Zhang,Jiaqi Yang,Bo An,Ke Wang,Dongxing Song,Huijuan Su
Gd 0.1 Ce 0.9-x Ga x O 2-δ (x = 0, 0.04,0.07, 0.12) are synthesized via the citric acid-EDTA combustion method as an electrolyte material for intermediate-temperature solid oxide fuel cells. XRD and Rietveld refinement revealed that the material exhibits a single-phase cubic fluorite structure. SEM and EDS analyses demonstrated that the incorporation of Ga ions improved the sample's density, increased the grain size, and provided better element dispersion. XPS analysis confirms that Ga-Gd co-doping leads to increased oxygen vacancy concentration and modifies the oxidation states of Ce. Impedance spectroscopy results indicated that Ga-Gd co-doped ceria has higher ionic conductivity and lower activation energy compared to Gd single-doped ceria. In comparison to Gd 0.1 Ce 0.9 O 1.95 , the best-performing Gd 0.1 Ce 0.83 Ga 0.07 O 2-δ achieved nearly a 26-fold increase in ionic conductivity and a 66 % reduction in activation energy. The clearance coefficient of Gd 0.1 Ce 0.83 Ga 0.07 O 2-δ reached 100.95, while the blocking factor decreased by nearly 73 % compared to Gd 0.1 Ce 0.9 O 1.95 . The incorporation of Ga ions led to a nearly one order of magnitude reduction in the dissipation of oxygen vacancy concentration in the space charge layer, with the potential decreasing from 0.3971V (Gd 0.1 Ce 0.9 O 1.95 ) to 0.3117V (Gd 0.1 Ce 0.83 Ga 0.07 O 2-δ ). Dielectric studies clarified the contribution of the Gd-Ga synergistic effect on interfacial polarization. In terms of single-cell performance, the NiO-GDC| Gd 0.1 Ce 0.83 Ga 0.07 O 2-δ |LSCF cell exhibited higher power density and current density, particularly showing a 42.9 % performance improvement at 650 °C compared to NiO-GDC|Gd 0.1 Ce 0.9 O 1.95 |LSCF. Density functional theory calculations indicated that the incorporation of Ga ions effectively suppresses the electronic conductivity of CeO 2 and significantly reduces the formation energy, binding energy, and migration barrier of oxygen vacancies. Therefore, Ga-Gd co-doping can be regarded as an effective strategy for enhancing the performance of ceria-based electrolytes in IT-SOFCs.
研究领域:
材料科学
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能源工程
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电化学
✓ 已验证
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DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2019
·
IF 4.084
Jin Li,Lichao Jia,Bo Chi,Jian Pu,Jian Li,Shimin Wang
As a mixed ion electronic conducting oxide , PrBaCo 2 O 5+δ is regarded as a promising solid oxide fuel cell cathode. To further improve PrBaCo 2 O 5+δ cathode's oxygen reduction reaction activity, porosity graded PrBaCo 2 O 5+δ -based cathode is prepared by screen printing technology. With a porous top and a comparative denser base, oxygen ions concentration and oxygen gas concentration in the cathode can be graded distributed. This concentration gradient works as driven force which can enhance the cathode catalytic activity . And distribution of relaxation time analysis is carried out to investigate cathodes performance optimization mechanism, the result shows that gradient porous PrBaCo 2 O 5+δ cathode's area specific resistance value is much lower than the traditional homogeneous porosity PrBaCo 2 O 5+δ cathode. The scaffold porosity modification promotes the cathode oxygen ions transfer processes without obvious impact on the cathode oxygen surface processes.
研究领域:
材料科学
·
能源科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）