Progress in Natural Science-Materials International
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2024
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IF 4.8
Min Dong,Qingya Sun,Zhihua Wang,Zixin Rui,Zhe Zhang,He Zhu,Si Lan
Layered LiNi x Co y Mn z O 2 (NCM) cathode materials have emerged as the best choice for high-energy-density lithium-ion batteries for powering electric vehicles. Despite significant research efforts, the understanding of complex structural dynamics during lithium (de-) intercalation still remains a subject of debate, especially in scenarios where morphology and composition vary. In this study, we carried out in situ high-energy synchrotron X-ray diffraction experiments on commercial NCM523 cathode materials in both single crystal and polycrystalline forms to probe the structural changes during charging and discharging in detail. Our findings reveal that both single crystal and polycrystalline materials exhibit typical H1–H2–H3 phase transitions. However, in polycrystalline NCM532, a monoclinic intermediate phase emerges between the H1 and H2 phases. During this process, symmetry reduces from R -3 m to C 2/ m , which is attributed to a shear distortion along the ab plane. In contrast, for single crystal materials, the H1 phase directly transforms into the H2 phase without the monoclinic phase. The observed monoclinic distortion significantly impacts structural stability and material cycling performance. This study provides new insight into the structural dynamics in NCM532 cathode materials, particularly concerning morphology-dependent behaviors, which could deepen our understanding of the relationship between NCM material structures and their performance.
研究领域:
材料科学
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电化学
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产品关联
DOI
高影响因子
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
2019
·Vol. 91
·期 2
·302-309
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IF 1.986
Zou Jian,Xiao Lei,Zhu Li,Chen Xuanyan
In this study, monoclinic vanadium dioxide (VO 2 ) nanoparticles were synthesized by one-step rapid hydrothermal treatment of a sol precursor, and the obtained products were examined using various analytical methods. Results indicated that monoclinic VO 2 nanoparticles could be obtained using ammonium metavanadate as the precursor at a high concentration of 2.37 M and the shortest duration was only 1 h. X-ray diffraction (XRD) revealed that VO 2 presented high crystallinity with a pure monoclinic phase. Phase transition latent heat of VO 2 was estimated to be 45.5 J/g. Furthermore, VO 2 powders were mostly composed of granules with a size distribution ranging from 20 nm to 100 nm. Monoclinic VO 2 nanoparticles were derived from the decomposition of the intermediate (NH 4 ) 2 V 4 O 9 .
Monoclinic vanadium dioxide (VO 2 ) nanoparticles can be synthesized by one-step rapid hydrothermal treatment of sol precursor with high concentration.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2013
·Vol. 97
·期 3
·990-995
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IF 2.107
Kuo Jiang,Songbai Liu,Yuan Li,Yaofei Li
Powders of zirconia doped with 8 mol% REO 1.5 (RE = Yb, Y, Gd, and Nd) were synthesized by using the sol–spray pyrolysis method. The effects of RE 3+ ionic radius on monoclinic (m) phase content of powders were investigated. The XRD results showed that the metastable tetragonal (t′) phase underwent a complete phase change to form m and cubic (c) phases after a heat treatment of 50–100 h at 1450°C. A cation size-dependent reduction in the m phase content of the REO 1.5 partially stabilized ZrO 2 powders was observed. The SEM–EDS analysis of the powders revealed that the RE 3+ concentrations in the c phases decreased with decreasing the RE 3+ ionic radius. These results indicate that the stabilizer concentration of the c phase can be attributed to RE 3+ ionic radii, resulting in different m phase contents. Compared to the REO 1.5 single doped ZrO 2 , the m phase contents of 8 mol% (RE 0.5 Yb 0.5 )–ZrO 2 (RE = Y, Gd, and Nd) powders were significantly reduced. The results prove that the stabilizer with a lower RE 3+ size is effective in reducing the m phase content of partially stabilized ZrO 2 after annealing at high temperatures.
研究领域:
材料科学
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陶瓷学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
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2023
·
IF 5.7
Zili Liu,Chong Wei,Yueying De,Songbin Zhang,Cheng Zhang,Xiaoqiang Li
High-entropy pyrochlore ceramics have received significant attention in the field of nuclear materials due to their ability to immobilize radioactive waste . In this study, a range of medium and high-entropy Ti-based pyrochlore powders were synthesized by a two-step method. Interestingly, a monoclinic phase was observed in some powders. An innovative experiment was conducted to adjust the cation ratio at the A site, which revealed that certain cations with larger ionic radii exhibit low solid solubility in the pyrochlore lattice, resulting in the formation of the monoclinic structure. To avoid the formation of monoclinic phase, the crystal structure was adjusted by introducing Zr 4+ at the B site. Based on the selection of single-phase powders, high-density pyrochlore ceramic bulks with uniform distribution of elements were prepared by spark plasma sintering . Here (Sm 1/5 Yb 1/5 Gd 1/5 Er 1/5 Dy 1/5 ) 2 Ti 2 O 7 bulks exhibited the smallest grain size at approximately 2.48 µm among all sintered samples and demonstrated a hardness of around 10.14 GPa.
研究领域:
核材料科学
·
无机材料科学
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产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2019
·
IF 4.029
Zhaoyubo Zeng,Yunzhong Liu,Feng Qian,Jianxiu Guo,Min Wu
Yttria , yttria-ceria and yttria-ceria-lanthana stabilized zirconia powders were prepared by coprecipitation . Their tetragonal-to-monoclinic phase (t→m) transformation was investigated by calcining the powders in a temperature range of 400–1400 °C for 2 h. The results show that after doping with 0.1 to 0.3 mol.% La 2 O 3 and calcining at 1400 °C in air, unusual redox behaviours of cerium were detected in the 1.5 mol.% Y 2 O 3 +5.5 mol.% CeO 2 co-stabilized zirconia. Grain refinement and a sharp reduction in oxygen vacancy concentration were observed simultaneously. The t→m transition was not found in the 0.1 mol.% La 2 O 3 doped zirconia but appeared in the cases with a higher dopant content. The changes are discussed with regards to the grain size, valence change of cerium, presence of oxygen vacancies, and segregation of the dopants at grain boundaries.
研究领域:
材料科学
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无机化学
✓ 已验证
产品关联
DOI
高影响因子
Nature Communications
·
2023
·Vol. 14
·期 1
·1-11
·
IF 16.6
Liao Fan,Yin Kui,Ji Yujin,Zhu Wenxiang,Fan Zhenglong,Li Youyong,Zhong Jun,Shao Mingwang,Kang Zhenhui,Shao Qi
Metastable metal oxides with ribbon morphologies have promising applications for energy conversion catalysis, however they are largely restricted by their limited synthesis methods. In this study, a monoclinic phase iridium oxide nanoribbon with a space group of C2/m is successfully obtained, which is distinct from rutile iridium oxide with a stable tetragonal phase (P42/mnm). A molten-alkali mechanochemical method provides a unique strategy for achieving this layered nanoribbon structure via a conversion from a monoclinic phase K 0.25 IrO 2 (I2/m (12)) precursor. The formation mechanism of IrO 2 nanoribbon is clearly revealed, with its further conversion to IrO 2 nanosheet with a trigonal phase. When applied as an electrocatalyst for the oxygen evolution reaction in acidic condition, the intrinsic catalytic activity of IrO 2 nanoribbon is higher than that of tetragonal phase IrO 2 due to the low d band centre of Ir in this special monoclinic phase structure, as confirmed by density functional theory calculations.
研究领域:
材料科学
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电化学
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催化
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Physical Chemistry Letters
·
2021
·
IF 6.475
Yaochang Yue,Jiyu Zhou,Qian Cheng,Xuning Zhang,Boxin Wang,Yanxun Li,Shilin Li,Ruiqi Cao,Kaiyuan Wang,Hui Wang,Huiqiong Zhou,Yuan Zhang
Bromine-containing metal halide all-inorganic perovskite CsPbI2Br exhibits excellent photoelectric performance and supreme thermal and structural stabilities; it is thus attractive for use as photoabsorbing layers in perovskite solar cells (PSCs). However, when steric hindrance molecules are introduced, the complicated phase transition mechanism and the difficult-to-control crystallization process in CsPbI2Br are not well understood. Here, we introduce a class of sterically hindered cesium naphthenate small molecules to control the crystallization process of CsPbI2Br films. Of interest, a new intermediate monoclinic phase has been discovered which leads to formation of dense and nonporous polycrystalline perovskite films. This phenomenon was also explained by density functional theory. The residues of steric hindrance molecules inside the CsPbI2Br film also improve its stability. We further show that as the ring number of cycloalkanes increases, the hindrance for the crystallization becomes more significant. Thus, by choosing the suitable steric hindrance, the optimal photovoltaic efficiency is 15.45%.
研究领域:
材料科学
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化学
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物理学
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纳米技术
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能源技术
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Chun Li,Yue Ma,Jian He,Hongbo Guo
Sandwich structure of cubic (C) phase/monoclinic (M) phase/C phase was formed in 8% mol Y 2 O 3 partially stabilized HfO 2 (Hf 0.92 Y 0.08 O 1.96 , YSH8) samples which were produced by sintering of YSH8 green body cold pressed from nano-powders of C phase at 1500 °C. The geometry of the sandwich structure was approximately tailored by controlling the sintering time. The YSH8 samples with sandwich structure from nano-powders yielded fracture toughness of 2.1–2.4 MPa m 0.5 , which was about 33% higher than that of conventional YSH8 sample sintered from micron powders. Both the experimental results and numerical simulation indicated that the fracture toughness is closely related to the geometry of the sandwich structure.
研究领域:
材料科学
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陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2015
·
IF 7.435
Wanjun Wang,Xingqiu Chen,Gang Liu,Zhurui Shen,Dehua Xia,Po Keung Wong,Jimmy C. Yu
A new visible-light-driven photocatalyst , monoclinic dibismuth tetraoxide (m-Bi 2 O 4 ), has been discovered. This simple oxide with mixed valent states (Bi 3+ and Bi 5+ ) has a band gap energy of 2.0 eV, and is responsive to wavelength up to 620 nm. The first-principle calculations within the hybrid density functional framework (HSE) indicate that m-Bi 2 O 4 is a typical indirect-gap semiconductor. It shows much higher photocatalytic degradation activity as well as photostability than some of the well-investigated highly efficient photocatalysts, such as CdS and Bi 2 O 3 . Not only typical dyes and colorless aromatic compounds, including rhodamine B, methyl orange, methyl blue, phenol and 4-nitrophenol, but also bacterial ( Escherichia coli ) cells can be effectively degraded/inactivated in the presence of m-Bi 2 O 4 . The electronic potential of band structure is studied and a photocatalytic mechanism is also proposed, in which both OH and direct h + oxidation play important roles in the degradation process. Our discovery highlights the potential of developing Bi 2 O 4 -based photocatalysts as a new class of highly active, stable and safe photocatalyst for versatile pollutant degradation and disinfection under visible light .
研究领域:
材料科学
·
环境科学
·
光催化
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半导体物理
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污染治理
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应用化学
✓ 已验证
DOI
高影响因子
Journal of the American Chemical Society
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2023
·
IF 15
Chengyuan Dong,Xinyao Wang,Zhipeng Zhu,Changhong Zhan,Xin Lin,Lingzheng Bu,Jinyu Ye,Yucheng Wang,Wei Liu,Xiaoqing Huang
Designing efficient formic acid oxidation reaction (FAOR) catalysts with remarkable membrane electrode assembly (MEA) performance in a direct formic acid fuel cell (DFAFC) medium is significant yet challenging. Herein, we report that the monoclinic-phased platinum–tellurium nanotrepang (m-PtTe NT) can be adopted as a highly active, selective, and stable FAOR catalyst with a desirable direct reaction pathway. The m-PtTe NT exhibits the high specific and mass activities of 6.78 mA cm–2 and 3.2 A mgPt–1, respectively, which are 35.7/22.9, 2.8/2.6, and 3.9/2.9 times higher than those of commercial Pt/C, rhombohedral-phased Pt2Te3 NT (r-Pt2Te3 NT), and trigonal-phased PtTe2 NT (t-PtTe2 NT), respectively. Simultaneously, the highest reaction tendency for the direct FAOR pathway and the best tolerance to poisonous CO intermediate can also be realized by m-PtTe NT. More importantly, even in a single-cell medium, the m-PtTe NT can display a much higher MEA power density (171.4 mW cm–2) and stability (53.2% voltage loss after 5660 s) than those of commercial Pt/C, demonstrating the great potential in operating DFAFC device. The in-situ Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy jointly demonstrate that the unique nanostructure of m-PtTe NT can effectively optimize dehydrogenation steps and inhibit the CO intermediate adsorption, as well as promote the oxidation of noxious CO intermediate, thus achieving the great improvement of FAOR activity, poisoning tolerance, and stability. Density functional theory calculations further reveal that the direct pathway is the most favorable on m-PtTe NT than r-Pt2Te3 NT and t-PtTe2 NT. The higher activation energy to produce CO and the relatively weaker binding with CO of m-PtTe NT result in the better CO tolerance. This work achieves remarkable FAOR and MEA performances of advanced Pt-based anodic catalysts for DFAFCs via a phase engineering strategy.
研究领域:
材料科学
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电化学
·
催化
·
燃料电池技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF NANOPARTICLE RESEARCH
·
2022
·Vol. 24
·期 11
·1-10
·
IF 2.533
Di Jing,Gai Xikun,Jamakanga Ropafadzo,Lou Jie,Zhu Minzhi,Li Yin,Yang Ruiqin,Ma Qingxiang
To investigate the correlation between electrochemical performance and physicochemical properties, three types of 1D WO 3 nanostructures were fabricated by hydrothermal method using K 2 SO 4 , Na 2 SO 4 , and (NH 4 ) 2 SO 4 as capping agents. Hexagonal phase was obtained with the assistant of Na 2 SO 4 and (NH 4 ) 2 SO 4 , while monoclinic phase was developed using K 2 SO 4 as agent. WO 3 nanostructures prepared by (NH 4 ) 2 SO 4 and Na 2 SO 4 exhibited superior specific capacitance (400 F/g and 388 F/g) relative to WO 3 prepared by K 2 SO 4 (259 F/g), suggesting hexagonal phase is more suitable for energy storage. The nanostructures prepared using Na 2 SO 4 exhibited inferior rate performance compared with those obtained by (NH 4 ) 2 SO 4 due to low specific surface area and high crystallinity. The electrochemical performance demonstrated nanostructures prepared by (NH 4 ) 2 SO 4 was surface-controlled whereas those using Na 2 SO 4 and K 2 SO 4 were battery-type material. These findings raise the prospects of developing tungsten oxide for energy storage. Graphical abstract
研究领域:
材料科学
·
电化学
·
纳米技术
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
SURFACE & COATINGS TECHNOLOGY
·
2013
·
IF 1.941
Kuo Jiang,Songbai Liu,Yu Luo,Qiang Li,Haiyang Wang
A polyglycol-assisted spreading deposition (PASD) method has been used to prepare the high-quality ZrO 2 thin film on single crystalline Si (111) substrate. The structure and composition of the films were studied by SEM, XRD and UV Raman techniques. Characterization results indicated that the ZrO 2 films were composed of nano-sized small particles and have a crack-free, dense and homogeneous microstructure. After a heat treatment of 10 min at 700–900 °C, the films showed a mixture of monoclinic and tetragonal ZrO 2 phases. And the grain sizes of monoclinic and tetragonal phases in the ZrO 2 films were 5–16 nm and 10–18 nm, respectively. In addition, the thin films of Y 2 O 3 -stabilized ZrO 2 (YSZ), La 2 Zr 2 O 7 , and the multilayer thin films of La 2 Zr 2 O 7 /YSZ were also fabricated by the PASD method.
研究领域:
材料科学
·
陶瓷
·
薄膜
·
表面科学
✓ 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）