OPTICAL MATERIALS
·
2012
·
IF 2.023
Chundong Li,Jinpeng Lv,Zhiqiang Liang,Shulong Yao
The blue band optical absorption and green luminescence of ZnO phosphors doping with aluminum are systematic studied. The Al content is varied from 0.01 at.% to 1 at.%. SEM images illustrated that Al doping can effectively suppress the ZnO grain growth. XRD results clearly manifest that the Al solubility limit in ZnO is around 0.1 at.%. It is also found that the E 1 (LO) vibration mode in the Raman spectra exhibits a good correlation with the blue band optical absorption and green photoluminescence. The results revealed that both V O 0 and V O + can give rise to the E 1 (LO) vibration mode. We conclude that the V O and O i defects are the dominant reason of the green photoluminescence in ZnO phosphors, in oxygen-deficient and oxygen-rich conditions, respectively.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Energy Materials
·
2020
·
IF 4.473
Chao Chen,Yao Sun,Linchun He,Masashi Kotobuki,Emil Hanc,Yu Chen,Kaiyang Zeng,Li Lu
The Garnet-type solid electrolyte Li7La3Zr2O12 (LLZO) showing high ionic conductivity and a wide electrochemical potential window is considered as one of the most promising candidates for solid-state batteries. Among various doping derivatives, the Al- and Ga-doped LLZO electrolytes are intensively studied because of their ability to enhance the stability of the cubic structure and to promote good sinter ability as well. Despite showing great similarities in site preference and sintering behavior, the Al and Ga doping derivatives differ by 1 order of magnitude in total ionic conductivity. Therefore, a comparative study on the doping characteristics of Al and Ga with respect to ionic conductivity and sintering behavior is necessary. Herein, we simultaneously introduced Al and Ga into Li sites (AlxGa0.25–x-LLZO) to study their influences on the microstructure and electrochemical properties of LLZO. The results show that Ga doping enables a higher conductivity than Al doping and largely promotes sinter ability at the same time. Compared to Al single doping (Al0.25), Ga-contained compositions (x < 0.25) show significant grain growth. Moreover, a slight inclusion of Ga (Al0.20Ga0.05) not only modifies the sintering behavior that results in a microstructure transition from fine grains of Al0.25 (5–20 μm) to abnormally large grains (several hundred micrometers) but also greatly enhances the conductivity, yielding a value that is 3 times higher. However, further increases in Ga ratio in AlxGa0.25–x results in marginal increases in conductivity. The total conductivity reaches a maximum of 1.19 × 10–3 S cm–1 for Ga single doping (Ga0.25) at room temperature. In addition, Al0.25 also shows fast ion conducting behavior along the grain boundaries with a conductivity of 8.30 × 10–4 S cm–1. Consequently, this study sheds lights on the different doping characteristics between Al and Ga, providing guidance for fine composition engineering of these two promising dopants.
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
·
2025
·
IF 6.3
Longyan Zhang,Gang Zhao,Xinming Wu
Molybdenum disulfide (MoS 2 ) has been widely studied in supercapacitors due to its high theoretical capacity, but the lower intrinsic conductivity limits its further application. In this paper, Al, P-doped MoS 2 was grown in situ on carbon cloth using a one-step hydrothermal method, respectively, and the implementation of the doping strategy increased the layer spacing of MoS 2 while synergistically improving the conductivity and specific capacitance of the material. The results show that Al, P doping not only enhance the conductivity of pristine MoS 2 by 35.8% and 21.1%, respectively, but also improve the specific capacitance from 284.4 F g -1 (at a current density of 0.5 A g -1 ) to 424.6 F g -1 and 449.2 F g -1 , respectively. Surprisingly, the ASC device assembled with Al 0.05 -MoS 2 as the positive electrode and P 0.05 -MoS 2 as the negative electrode achieved an energy density of 30.07 Wh kg -1 at a power density of 1259.99 W kg -1 . These results demonstrate the superiority of Al, P-doped MoS 2 nanoflowers for high-performance supercapacitor applications.
研究领域:
材料科学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2022
·Vol. 33
·期 33
·24986-24994
·
IF 2.779
Cheng Li-Qian,Jiang Guozheng,Ma Zhenhua,Xu Ze,Yu Minghao,Lu Jingtong,Chen Kai
Al-doped BaZr 0.2 Ti 0.8 O 3 (BZT20) ceramics were prepared by solid-state sintering, and the relaxation degree of phase transition was tailored effectively. The microstructure, dielectric properties, ferroelectric properties, and electrocaloric (EC) performance of Al 2 O 3 -doped BZT20 ceramics were studied, respectively. The results show that Al 2 O 3 doping induces changes in Curie temperature and dielectric properties. When the additive amount of Al 2 O 3 is 1.25 at.%, the Curie temperature drops to around room temperature (RT), and the dielectric loss is lower than that of pure BZT20 ceramics. The diffusion constant γ reaches a minimum value of 1.57 when the Al 2 O 3 content is 1.25 at.%, indicating that a relatively large latent heat would be gathered while there is a phase transition. As a result, an enhanced EC response of ∆ T max = 0.293 K near RT is obtained when the Al 2 O 3 content is 1.25 at.%, which is 1.6 times that of pure BZT20. It is also impressive that a wide working temperature range can be obtained, that is, T span = 73 K for BZT20 ceramics with 1 at.% of Al 3+ ionic content.
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2024
·
IF 8.1
Yang Yang,Honghao Deng,Liying Liu,Jiahong Pan,Ping Chen,Zhicong Shi
O3-type Cu/Fe/Mn-based layered oxides are regarded as promising cathode materials for sodium-ion batteries due to the abundance of elements in the Earth's crust and the imperative for large-scale energy storage. However, these materials still encounter some challenges, including low capacity and insufficient rate performance. In this study, Al-doped, cobalt-free, and nickel-free Na 0.9 Cu 0.18 Fe 0.3 Mn 0.52-x Al x O 2 (x = 0, 0.03, 0.05, 0.08) are successfully synthesized by using the solid-state method to introduce non-electrochemically active elements to stabilize the crystal structure and enhance the electrochemical performance. The impact of Al-doping is comprehensively analyzed by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), galvanostatic intermittent titration technique (GITT), and electrochemical impedance spectroscopy (EIS). Al-doping effectively enhances the diffusion coefficient of Na + , reduces the Jahn-Teller effect caused by Mn 3+ and mitigates the transition from O3 to P3 phase. Finally, it stops the partial phase transitions from O3 to P3, which can be found in pristine oxide without Al-doping during charge-discharge cycling. Notably, the Na 0.9 Cu 0.18 Fe 0.3 Mn 0.47 Al 0.05 O 2 electrode exhibits a reversible capacity of 123.89 mAh g −1 at 0.1 C, a capacity retention rate of 91.1 % after 200 cycles at 1 C, and a discharge capacity of 66.36 mAh g −1 at a high rate of 5 C.
研究领域:
材料科学
·
能源存储与转换
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2021
·
IF 5.316
Meixia Wu,Yifeng Han,Xiang Zhou,Xihui Liang,Shuang Zhao,Man-Rong Li
Controlling and modulating the magnitude and signs of electric polarization in multiferroics are very important for practical applications. The magnetoelectric effect in multiferroic materials enables the control and tailor of electric polarization by a magnetic field or vice versa . However, there are rare investigations about the mutual control of the magnitude and signs of electric polarization in multiferroics . Here, we successfully synthesized single crystals of Y-type hexaferrites Ba 0.8 Sr 1.2 Co 2 Fe 12- x Al x O 22 ( x = 0 and 1.08) via flux method. The magnetization, magnetodielectric and magnetoelectric properties were investigated. We found that Al-doping increased the conical magnetic structure transition temperatures and enhanced the magnetoelectric properties. Most importantly, both samples exhibited reversal and non-reversal polarizations at low and high temperatures, respectively. In addition, Al-doping can stabilize the non-reversal ferroelectric polarization, possibly originating from the different field-dependent magnetic structure transitions.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2025
·
IF 8.2
Yu Wu,Wenting Ji,Zhihua Xu,Yuqin Huang,De Li,Yuanchuan Li,Yong Chen
In Li-ion batteries (LIBs), the phenomenon of memory effect has only been found in a few two-phase electrode materials such as olivine LiFePO4, anatase TiO2, and Al-doped Li4Ti5O12, which is attributed to the Li-ion exchange between adjacent vacant Li and Fe sites in LiFePO4 and the Al-ion exchange between 8a and 16c sites in Al-doped Li4Ti5O12. Here, the Al-doped LiCrTiO4 was successfully synthesized by the spray-drying method and high-temperature sintering, which also exhibits the memory effect during only the charging process. The X-ray diffraction (XRD) and electrochemical results indicate that the saturated Al-doping level corresponds to the Al:Ti ratio of ca. 0.25 for LiCrTiO4, and the memory effect increases with the Al-doping level evidently. According to the in situ XRD and magic-angle spinning nuclear magnetic resonance results, the Al3+ ions are doped at the 8a sites, the Li ions hop between 8a and 16c sites during the charging and discharging processes, and the Li ions further hop from the 16c site to the 16d site after deeply discharging and move back in the subsequent charging process. Therefore, the memory effect of Al-doped LiCrTiO4 should originate from the reversible exchange of Li ions between 16c and 16d sites, and it is a common strategy to cause the memory effect in LIBs by inducing another reversible ionic migration in the electrode materials to affect the normal Li-ion extraction/insertion.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Coatings
·
2024
·Vol. 14
·期 9
·1097
·
IF 2.9
Jiaxin Liao,Lin Chen,Luyang Zhang,Xunlei Chen,Cheng Xu,Tianyu Li,Jing Feng
Environmental barrier coatings (EBCs) are widely used to protect ceramic matrix composites (CMCs, SiCf/SiC, and Al2O3f/Al2O3), and they should have low thermal expansion coefficients (TECs) matching the CMCs and excellent mechanical properties to prolong their lifetime. Current EBC materials have disadvantages of phase transitions and insufficient mechanical properties, which affect their working temperatures and lifetime. It is necessary to develop new oxide EBCs. Ytterbium tantalate (YbTaO4) is a stable and novel EBC material, and we have improved the mechanical properties and TECs of Yb1−xAlxTaO4(x = 0.05, 0.1, 0.2, 0.3, 0.4, 0.5) ceramics by replacing Yb with Al. XRD, SEM, and EDS are used to verify the crystal and microstructures, and nano-indentation is used to measure the modulus and hardness when changes in TECs are measured within a thermal expansion device. The results show that the phase structure of Yb1−xAlxTaO4(x = 0.05, 0.1, 0.2, 0.3, 0.4, 0.5) is stable at 25–1400 °C within air atmosphere, and their high-temperature TECs (6.4–8.9 × 10−6K−1, 1400 °C) are effectively regulated by introductions of different contents of Al, which enlarge their engineering applications for SiCf/SiC and Al2O3f/Al2O3CMCs. The evolutions of TECs are analyzed from structural characteristics and phase compositions, and the increased TECs make Yb1−xAlxTaO4potential EBCs for Al2O3matrixes. Due to the high bonding strength of Al–O bonds, hardness, as well as Young’s modulus, are enhanced with the increasing Al content, with Yb1−xAlxTaO4(x = 0.05, 0.1, 0.2, 0.3, 0.4, 0.5) having a nano-hardness of 3.7–12.8 GPa and a Young’s modulus of 100.9–236.6 GPa. The TECs of YbTaO4are successfully regulated to expand their applications, and they match those of Al2O3and SiC matrixes, as well as displaying improved mechanical properties. This work promotes applications of YbTaO4as potential EBCs and provides a new way to regulate the TECs of tantalates.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
Frontiers of Materials Science
·
2015
·Vol. 9
·期 4
·366-372
·
IF 1
Xia Yu,Ma Liang,Lu Hui,Wang Xian-Ping,Gao Yun-Xia,Liu Wang,Zhuang Zong,Guo Li-Jun,Fang Qian-Feng
Garnet-like Li 6.8 La 3 Zr 1.8 Bi 0.2 O 12 (LLZBO) + x mol.% Al 2 O 3 ( x = 0, 1.25, 2.50) lithium ionic electrolytes were prepared by conventional solid state reaction method under two different sintering temperatures of 1000°C and 1100°C. XPS, induced coupled plasma optical emission spectrometer (ICP-OES), XRD and AC impedance spectroscopy were applied to investigate the bismuth valance, lithium concentration, phase structure and lithium ionic conductivity, respectively. Electrical measurement demonstrated that ionic conductivity of Al-added LLZBO compounds could be obviously improved when the sample sintering temperature increased from 1000°C to 1100°C. The highest ionic conductivity 6.3×10 -5 S/cm was obtained in the LLZBO-1.25%Al sample sintered at 1100°C, in consistent with the lowest activation energy 0.45 eV for the lithium ion migration. The mechanism related with good ionic conductivity in the Al-added LLZBO sample was attributed to the lattice distortion induced by the partial Al substitution at Zr sites, which is helpful to improve the migration ability of Li ions in lattice.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2025
·
IF 8.3
Hanwei Zhao,Bowen Zhang,Enze Fan,Zhuanfang Zhang,Guohua Dong,Wenzhi Zhang,Liming Bai,Ming Zhao,Dong-Feng Chai,Xiaoming Huang
CoMoO 4 is a promising oxygen evolution reaction (OER) catalyst owing to its distinct crystallographic configuration and redox versatility. However, its practical applications remain limited by its suboptimal active site density and inefficient charge-transport mechanisms. To address these challenges, a one-step hydrothermal method is developed to introduce Al atoms into the CoMoO 4 framework, yielding an Al-doped electrocatalyst (Al–CoMoO 4 -1/NF) featuring enhanced functionality. Al–CoMoO 4 -1/NF achieves an OER current density of 10 mA cm −2 at an overpotential of 184 mV, demonstrating a Tafel slope of 55.6 mV dec −1 . In full water-splitting configurations, the Al–CoMoO 4 -1/NF(+)||Pt/C/NF(−) electrolyzer attains 10 mA cm −2 at 1.52 V, outperforming various nonprecious-metal-based systems. Al integration regulates ∗OH intermediate adsorption equilibrium and strengthens interactions with oxygenated species. Al incorporation considerably reduces charge-transfer resistance and accelerates reaction kinetics. The larger specific surface area of the Al-doped structure exposes more active sites and increases the electrode/electrolyte interfacial contact area, improving catalytic activity. These synergistic effects enhance intrinsic activity and mass-transport efficiency. Leveraging abundant Al for structural modulation, this study advances the rational design of high-performance, cost-efficient OER catalysts for sustainable energy conversion.
研究领域:
材料科学
·
电化学
·
能源转换
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2016
·
IF 2.758
Zhongli Hu,Hongdong Liu,Haibo Ruan,Rong Hu,Yongyao Su,Lei Zhang
Li 7 La 3 Zr 2 O 12 (LLZO) has cubic garnet type structure and is a promising solid electrolyte for next-generation Li-ion batteries. In this work, Al-doped LLZO was prepared via conventional solid-state reaction. The effects of sintering temperature and Al doping content on the structure and Li-ion conductivity of LLZO were investigated. The phase composition of the products was confirmed to be cubic LLZO via XRD . The morphology and chemical composition of calcined powders were investigated with SEM, EDS , and TEM . The Li-ion conductivity was measured by AC impedance. The results indicated the optimum sintering temperature range is 800–950 °C, the appropriate molar ratio of LiOH·H 2 O, La(OH) 3 , ZrO 2 and Al 2 O 3 is 7.7:3:2:(0.2–0.4), and the Li-ion conductivity of LLZO sintered at 900 °C with 0.3 mol of Al-doped was 2.11×10 −4 S cm −1 at 25 °C.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Molecular Catalysis
·
2022
·
IF 5.089
Chunsheng Wan,Xiaofeng Wei,Guohui Cai,Dalin Li,Yingying Zhan,Yihong Xiao,Lilong Jiang
Al-doped Co 3 O 4 and CoO are prepared from Co‒Al hydrotalcite by calcination in air and N 2 atmospheres, and characterized by TG-DTA, XRD, SEM, N 2 adsorption, Raman, XPS, and H 2 -TPR. Co‒Al hydrotalcite is oxidized to Co(Co,Al) 2 O 4 in air accompanying with the collapse of layered structure, while in N 2 it decomposes to Co(Al)O that remains the plate morphology of hydrotalcite. In both cases, Al 3+ is doped into the lattice of cobalt oxides, leading to marked changes in the crystal size, surface state, and reducibility. Especially, Al-doped CoO shows smaller crystal size (4.1 nm), larger surface area (172 m 2 g ‒1 ), and higher degree of structural disorder than Al-doped Co 3 O 4 . Meanwhile, the Al-doped cobalt oxides show different reducibilities to those of Co 3 O 4 and CoO, indicating a strong interaction between cobalt and aluminum. The N 2 -calcined sample exhibits higher activity for benzene combustion than the air-calcined sample as well as a relatively good stability during heating/cooling cycles and a good long-time durability. Under the reaction atmosphere, Co(Al)O is transferred to Co(Co,Al) 2 O 4 . The resulting Co(Co,Al) 2 O 4 remains the original plate morphology and textural property and presents abundant surface adsorbed oxygen species, which accounts for its high activity.
研究领域:
催化化学
·
材料科学
✓ 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）