JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Panpan Wang,Jing Wang,Huangyue Cai,Xiao Shan,Han Zhang,Guoliang Ren,Junjie He,Lirong Luo,Xiaofeng Zhao
A series of high entropy niobates with cation at A-site varying in size disorder and mass disorder is designed. High entropy niobates are all monoclinic structures with uniform rare-earth element distribution, but different space groups, which are closely related to the average radius at A-site. High entropy niobates possess excellent sintering resistance and ultra-low thermal conductivity due to stronger phonon-point defect scattering and shorter phonon lifetime. The effect of high entropy on average grain size and thermal conductivity is inversely proportional to size disorder. Moreover, the radiative heat transfer of (Dy 0.2 Ho 0.2 Er 0.2 Y 0.2 Yb 0.2 )NbO 4 is substantially reduced due to the co-doping of active multi-component Dy 3+ , Er 3+ , and Yb 3+ , which broadens the range of intrinsic absorption band and improves lattice absorption derived from lattice distortion. Besides, the (La 0.2 Nd 0.2 Sm 0.2 Eu 0.2 Y 0.2 )NbO 4 exhibits an ultra-high thermal expansion coefficient (12.34 ×10 −6 K −1 , 673 °C). The excellent thermophysical properties imply that high entropy niobates are more promising thermal barrier coating materials.
研究领域:
材料科学
·
热力学
✓ 已验证
DOI
高影响因子
Advanced Energy Materials
·
2021
·Vol. 11
·期 12
·2003755
·
IF 29.368
Yu Sun,Ran Li,Xiaoxuan Chen,Jing Wu,Yong Xie,Xin Wang,Kaikai Ma,Li Wang,Zheng Zhang,Qingliang Liao,Zhuo Kang,Yue Zhang
Perovskites (ABX 3 ) are promising oxygen evolution reaction (OER) catalysts for their highly intrinsic activity. The in-depth understanding and the adjustment of dynamic reconstruction of active phases for perovskites in OER are still a daunting challenge. Here, a refined A-site management strategy is proposed for perovskite oxides, which facilitates the surface reconstruction of the B-site element based active phase to enhance the OER performance. Electrocatalyst LaNiO 3 displays a dynamic reconstruction feature during OER with the growth of a self-assembled NiOOH active layer, based on the in situ electrochemical Raman technology. Precise A-site Ce doping lowers the reconstruction potential for the active phase and the dynamic structure–activity correlation is well established. Theoretical calculations demonstrate that A-site Ce substitution upshifts the O 2p level for greater structural flexibility with optimized oxygen vacancy content, thereby activating the B-site atom and promoting the active phase reconstruction. These results suggest that A-site management prompts the B-site element based active phase dynamic reconstruction via engineered X-site content as a bridge. Therefore, indicating the strong correlation of each-site component in perovskite oxides during OER and deepening the understanding of the fundamental processes of the structural transformation and further benefiting the accurate design of high-efficiency perovskite OER electrocatalysts.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Yingchao Wang,Jingjing Wu,Xianglong Lu,YuMin Guo,Huining Zhao,Xin Tang
The bifunctional catalysts which can improve both oxygen evolution (OER) and oxygen reduction reaction (ORR) activity are highly desirable for fuel cells, metal-air batteries and water splitting. Here, we report a perovskite structure Sr 0.9 M 0.1 RuO 3-δ (SMRO, M=K, Na, Ag) synthesized via sol-gel method performing excellent bifunctional catalytic activity. With the metal ion (M + ) doping in A-site, X-ray photoelectron spectroscopy analysis reveals that oxygen vacancy and lattice oxygen are introduced into the structure, which is confirmed as the primary reason for the improvement of catalytic activity. The highest OER and ORR activity among these four samples is observed in Sr 0.9 Ag 0.1 RuO 3 (SARO). This work may shed light on the designing of high-efficiency bifunctional OER/ORR electrocatalysts .
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2022
·Vol. 10
·期 17
·9419-9426
·
IF 14.511
Jiabiao Yan,Jing Zhu,Dawei Chen,Shuai Liu,Xu Zhang,Shoushan Yu,Zhenhua Zeng,Luhua Jiang,Fanglin Du
Ruthenium-based pyrochlore oxides (A2Ru2O7) have emerged recently as state-of-the-art catalysts for acidic water oxidation; however, their stability still needs to be further improved. Exploring the relationship between the A-site cation and the structure of the active site (Ru) is highly desirable for designing efficient electrocatalysts. Herein, we rationally manipulate the substitution of the A-site atoms in Y2Ru2O7 (YRO) by Ho3+, which has an identical ionic radius to Y3+ but higher electronegativity due to the 4f electron effect. It was demonstrated that the higher electronegativity could enlarge the Ru–O–Ru bond angle and reduce the Ru–O bond length, mitigating the RuO6 octahedral distortion in Ho2Ru2O7 (HRO) for enhancing the intrinsic OER activity. Compared with other pyrochlore oxides, HRO displayed an ultralow overpotential of 215 mV @ 10 mA cm−2 with lower Ru content and higher mass activities, showing long-term (>60 h) stability in acid media. Density functional theory (DFT) calculations revealed that the higher electronegativity of Ho could strengthen the Ru–O covalency, thereby optimizing the free energy of oxygen species (ΔGOOH* − ΔGO2) for better catalytic activity. In addition, the higher electronegativity could reduce the oxygen vacancies and improve the formation energy of oxygen vacancies for better resistance to Ru dissolution. This work reveals the inherent relationship of the A-site atom electronegativity, the lattice structure of the active site, and the activity–stability of the catalysts.
研究领域:
材料科学
·
电化学
·
催化
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2022
·
IF 6.364
Jing-Hui Zhang,Fang-Ze Han,Cheng-Xin Li,Shan-Lin Zhang
Recently, SrTi 0.3 Fe 0.7 O 3−δ (STF) has been investigated as a highly stable oxygen electrode material for solid oxide electrochemical cells (SOCs) with a sufficiently low resistance for cell operation at temperatures of > 700 °C. However, in general, the STF electrode performance is limited at temperatures of ≤ 700 °C due to the low oxygen surface exchange coefficient, which is mainly caused by high Sr surface segregation. To improve the electrode performance, Sr 0.9 (Ti 0.3 Fe 0.7 )O 3−δ (A-STF) with an A-site-deficient design is developed to reduce the Sr content and thus reduce the Sr surface segregation, thereby providing a unique combination of excellent oxygen electrode performance and long-term stability. The A-site deficiency reduces the electrode polarization resistance by > 3 times at 600 °C and clearly improves the oxygen diffusion and surface exchange coefficients due to the decrease of Sr surface segregation. The A-STF electrode exhibits stable performance in the fuel cell and electrolysis modes at 1 A cm −2 > 1200 h. The stability of STF-based oxygen electrodes in a CO 2 -enriched atmosphere is investigated, and the results indicate that A-STF exhibits excellent CO 2 tolerance.
研究领域:
材料科学
·
能源科学
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2019
·Vol. 7
·期 19
·12176-12190
·
IF 10.733
Chao-Jie Ma,Ya Chen,Cheng Zhu,Qi Chen,Wei-Li Song,Shuqiang Jiao,Haosen Chen,Daining Fang
Perovskite materials (ABX3) are significant for energy storage and conversion, and most of the electrochemical processes are currently known to link with the reaction from the active B site. Here, a novel electrochemical active reaction is observed from the A site in perovskite bismuth ferrite (BiFeO3) nanoparticles. With bismuth ion extraction from the A site, single-phase BiFeO3 is found to convert into two phases, namely, Bi2O3 and residual Bi-deficient BiFeO3, and these irreversible products undergo additional separate electrochemical processes in the subsequent cycles. The fundamental understanding suggests that the extracted Bi3+ ions play a dominant role in the electrochemical process via redox reactions of Bi3+ ⇌ Bi2+ ⇌ Bi0. Interestingly, such an electrochemical reaction involving the A site could also be suppressed via heteroatom doping at the A site (yttrium ions), which effectively supports the mechanism of ion extraction. The perspectives for the novel mechanism in electrochemical energy storage are further discussed.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2023
·
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
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2022
·
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
·
电化学
·
能源技术
✓ 已验证
DOI
高影响因子
ACS Applied Energy Materials
·
2022
·
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
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
Sustainable Energy & Fuels
·
2025
·
IF 4.1
Zepeng Li,Yanfeng Ge,Weilin Jia,Mingrun Du,Xueting Yi,Yu Ma,Jingya Wang,Bo Liu,Yuan Li,Huanbin Li
High-entropy perovskites (HEPs) have emerged as promising cathode materials for solid oxide fuel cells (SOFCs) due to their tunable properties and enhanced electrochemical performance. In this study, a series of iron-based HEP cathodes, AFeO₃ (A = Sr, Ba, Bi, La, Pr, Nd, Sm), were synthesized via a high-entropy strategy to investigate the influence of A-site composition on structural and electrochemical properties. The introduction of low-valence A-site elements (Sr, Ba) and Bi³⁺ with highly polarized 6s² lone pair electrons was found to facilitate the formation of oxygen vacancies and modulate the valence state of iron ions, leading to lattice distortion and a phase transformation from cubic to orthorhombic structures. Electrochemical impedance spectroscopy (EIS) combined with distribution of relaxation time (DRT) analysis revealed distinct oxygen ion transport mechanisms under varying conditions. The incorporation of divalent and bismuth elements reduced the formation energy of oxygen vacancies and promoted the formation of high-valence iron ions, significantly enhancing oxygen adsorption, transport, and reduction capabilities. The optimized cathode, (Sr₀.₂Ba₀.₂Bi₀.₂La₀.₂Pr₀.₂)FeO₃, exhibited an area-specific resistance (ASR) of 0.03 Ω cm² at 800 °C, outperforming conventional Fe-based perovskite cathodes. This work provides valuable insights into the design of high-performance HEP cathodes for SOFCs, highlighting the critical role of A-site composition in optimizing oxygen reduction reaction (ORR) kinetics and thermal expansion behavior.
研究领域:
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Hantao Wang,Yu Zou,Haoqing Guo,Wenjin Yu,Xinyu Guo,Xiangdong Li,Zehao Zhang,Ganghong Liu,Shuang Yang,Zhenyu Tang,Bo Qu,Zhijian Chen,Lixin Xiao
To address the toxicity and stability issues of traditional lead halide perovskite solar cells (PSCs), the development of lead-free PSCs, such as Cs2AgBiBr6 solar cells, is of great significance. However, due to the low defect formation energy of Cs2AgBiBr6, a large number of vacancies, including A-site vacancies and X-site vacancies, form during the fabrication process of the Cs2AgBiBr6 film, which seriously damage the performance of the devices. The traditional phenylethylammonium (PEA) cation, mainly focusing on passivating A-site vacancies, is incapable of reducing X-site vacancies and so results in a limited performance improvement in Cs2AgBiBr6 solar cells. Herein, inspired by the capability of the Lewis base to coordinate with metal cations, a series of N-heterocyclic amines are introduced to serve as a dual-site passivator, reducing A-site and X-site vacancies at the same time. The highest power conversion efficiency of modified Cs2AgBiBr6 solar cells has been increased 36% from 1.10 to 1.50%. Further investigation reveals that the higher electron density of additives would lead to a stronger interaction with metal cations like Ag+ and Bi3+, thus reducing more X-site defects and improving carrier dynamics. Our work provides a strategy for passivating perovskite with various kinds of defects and reveals the connection between the coordination capability of additives and device performance enhancement, which could be instructive in improving the performance of lead-free PSCs.
研究领域:
材料科学
·
太阳能
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2024
·
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
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）