POWDER TECHNOLOGY
·
2024
·
IF 4.5
Huifeng Xu,Pengfei Wang,Saiwei Luan,Lixia Cheng,Zhenxiao Fu,Xiuhua Cao,Lei Zhang,Shuhui Yu,Rong Sun
Conventionally, tetragonality in BaTiO 3 powder is attributed to grain size, disregarding the role of Ba/Ti ratio. However, our study reveals a significant impact of Ba/Ti ratio on tetragonality in BaTiO 3 . With an increase in Ba/Ti ratio from 0.990 to 1.010, particle size remains around 200 nm. Tetragonality initially rises from 1.006 to a maximum of 1.0092 at Ba/Ti = 1.000, then decreases to 1.005. Lower tetragonality is associated with Ba or Ti vacancies, using density functional theory (DFT), we analyzed the electron density and lattice distinction in BaTiO 3 powders. Both Ba and Ti vacancies affect lattice distortion, the Ti vacancies leading to more significant lattice expansion and lower tetragonality than Ba vacancies. Using this powder, we fabricated high-density BaTiO 3 ceramics and multi-layer ceramics capacitors (MLCCs) with X7R temperature stability (−55 to 125 °C, ±15% coefficient) and excellent reliability. This strategy has broad implications for tetragonal BaTiO 3 nanopowders and MLCCs development.
研究领域:
材料科学
·
无机非金属材料
·
电子陶瓷
·
固态化学
·
功能材料
✓ 已验证
DOI
高影响因子
MATERIALS & DESIGN
·
2017
·
IF 4.364
Puhong Wen,Lili Ai,Taotao Liu,Dengwei Hu,Fangyi Yao
The regular orthorhombic Nb 2 O 5 (O-Nb 2 O 5 ) rectangle nanosheets dominantly exposed (010) facet are synthesized by a hydrothermal topological reaction with a precursor of K 4 Nb 6 O 17 ·4.5H 2 O (KNbO). The structure and morphology of the samples obtained at different temperatures and pH values of reacting solution are investigated. The results suggest that there are two topological reactions in this process. One is the acid-exchanging reaction transforming into H 4 Nb 6 O 17 ·3H 2 O (HNbO) nanosheets from KNbO rectangle nanosheets , and the other is dehydration reaction transforming into O-Nb 2 O 5 rectangle nanosheets from HNbO nanosheets. And the {010} facets of O-Nb 2 O 5 crystal are transformed from the {010} facets of HNbO crystal in the ingenious topological reaction. The photoelectric performance of the obtained O-Nb 2 O 5 nanosheets is evaluated by decomposing water to H 2 under 370 nm UV light illumination and measuring the accompanying photocurrent . The photocurrent density is 680 nA·cm − 2 generated by splitting water with O-Nb 2 O 5 nanosheets as photocatalyst , and it is 4.3 times of the contrast sample. The result indicates that the (010) facet of O-Nb 2 O 5 is one of the highest photocatalytic active surfaces and shows high photoelectric conversion efficiency. Thus, the O-Nb 2 O 5 nanosheets dominantly exposed (010) facet have potential applications in photocatalyst and photoelectric nanodevices .
研究领域:
材料科学
·
光催化
·
纳米材料
·
无机化学
·
能源材料
✓ 已验证
DOI
高影响因子
Nano Energy
·
2016
·
IF 11.553
Zhaoqiang Li,Caixia Li,Xiaoli Ge,Jingyun Ma,Zhiwei Zhang,Qun Li,Chengxiang Wang,Longwei Yin
Reduced graphene oxide (RGO) wrapped metal-organic frameworks (MOFs) derived cobalt doped porous carbon polyhedrons synthesized via a carbonization process, are for the first time used for sulfur immobilizers (RGO/C–Co-S) as cathodes for high performance lithium-sulfur (Li–S) batteries. The RGO/C–Co–S cathode exhibits greatly improved electrochemical performance, showing excellent specific capacity of 949 mAh g −1 at 300th cycle at a current density 0.3 A g −1 , displaying enhanced rate capability with specific capacity of 772, 704 and 606 mAh g −1 at current density of 0.5, 1 and 2 A g −1 , respectively. The synergetic effect of MOFs-derived porous carbon, homogeneously distributed Co nanoparticles and RGO nanosheets simultaneously contributes to the confinement of sulfur species. The presence of abundant mesopores and micropores is conducive to immobilize large amounts of S species. The homogenously inlaid ultrafine Co nanoparticles can further immobilize sulfur by chemical interactions between Co and S/polysulfides. The RGO nanosheets tightly wrapped on carbon hosts act as barrier layers to prevent polysulfides from diffusing out of the matrix, further suppressing shuttle effect. The porous structure and the RGO can effectively alleviate the volume changes resulted from charge–discharge process. This design strategy can be inspiring for MOF-derived materials in energy storage applications .
研究领域:
材料科学
·
电化学
·
能源存储
·
纳米材料
·
电池技术
✓ 已验证
DOI
高影响因子
Materials Science & Engineering C-Materials for Biological Applications
·
2013
·Vol. 33
·期 8
·5044-5050
·
IF 2.404
Y.H. Xia,B.P. Zhang,C.X. Lu,L. Geng
In this paper, corrosion resistance of the Mg–4.0Zn–0.2Ca alloy was modified by micro-arc oxidation (MAO) process. The microstructure and phase constituents of MAO layer were characterized by SEM, XRD and X-ray photoelectron spectroscopy (XPS). The corrosion resistance of MAO treated Mg–4.0Zn–0.2Ca alloy in the simulated body fluid were characterized by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The microstructure results indicated that a kind of ceramic film was composed by MgO and MgF 2 was formed on the surface of Mg–4.0Zn–0.2Ca alloy after MAO treatment. The electrochemical test reveals that the corrosion resistance of MAO treated samples increase 1 order of magnitude. The mechanical intensity test showed that the MAO treated samples has suitable mechanical properties.
研究领域:
生物医学工程
·
材料科学
·
生物材料
·
表面工程
·
腐蚀科学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·Vol. 48
·期 13
·18876-18883
·
IF 5.532
Zhixin Ma,Yang Qi,Jun Wang,Xiaoguo Bi,Xu-dong Liu,Xiaodong Li,Ji-guang Li,Xudong Sun
SrTiO 3 is a promising thermoelectric material for applications in harsh environments, owing to its excellent thermoelectric (TE) properties and high-temperature stability. The effect of annealing in carbon powders on the TE properties of SrTiO 3−δ in the [111] direction was experimentally investigated and analysed using first-principles calculation. The electrical conductivity of the SrTiO 3−δ single crystals in the [111] direction increases with an increase in annealing temperature in the range of 1573–1673 K, which is opposite to that in the [510] direction as shown in a previous experiment. This is attributed to the different variation trend of carrier concentration. First-principle calculation results show that the carrier concentration in the [111] direction increases with increasing oxygen vacancy concentration, but it is the opposite in the [510] direction. Strong anisotropy of carrier concentration should be caused by the difference in atomic arrangement, making difference in the amount of free electrons that maybe constrained at high oxygen vacancy in different directions. Although the SrTiO 3−δ single crystal annealed at 1573 K shows a lower electrical conductivity, it obtains higher power factor with the maximum value of 2.24 mW m −1 K −2 at 323 K, which is predominantly due to its higher effective mass. It also yields the highest ZT value of 0.18 at 873 K owing to the lower thermal conductivity . The results of this study are imperative for the design and development of perovskite TE materials.
研究领域:
材料科学
·
凝聚态物理
·
热电材料
·
晶体学
·
固体化学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2020
·
IF 4.65
Zhuangzhi Wu,Min Ouyang,Dezhi Wang,Xinli Liu
The photoelectrocatalytic water splitting of molybdenum disulfide is hindered by the intrinsic large electrical resistance among adjacent layers, serious photo-generated carrier recombination and limited utilization of visible light . Herein, we construct MoS 2 /MoO 2 heterostructures via a facile in situ hydrothermal route, in which a Schottky junction is established between the MoS 2 semiconductor and metallic MoO 2 . As a result, the photoelectrochemical current density of MoS 2 /MoO 2 is enhanced about 1.6 times than that of pure MoS 2 , achieving −10.3 mA cm −2 at −1.8 V vs. SCE, which can be attributed to the reduced electron transfer resistance, enlarged photo-generated carrier separation efficiency and enhanced light absorption due to the presence of metallic MoO 2 .
研究领域:
材料科学
·
物理化学
·
能源化学
·
半导体催化
·
光电子学
✓ 已验证
DOI
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2017
·
IF 5.401
Zhongming Wang,Kun Wang,Xiaoying Peng,Qiang Geng,Xun Chen,Wenxin Dai,Xianzhi Fu,Xuxu Wang
The photoconductivity and the gas sensing property of TiO 2 at room temperature under ultraviolet (UV) irradiation were compared with those under visible light irradiation (≥420 nm), respectively. It was found that UV light could cause the photoconductivity of TiO 2 and its sensing response to both ethylene and oxygen, while the visible light at 420 nm could cause the photoconductivity of TiO 2 and its sensing response to oxygen but not to ethylene. This indicates that the photo-assisted gas sensing performance of TiO 2 was dependent on its light-excited behavior: The intrinsic excitation of TiO 2 induced by UV light could produce both the holes and electrons, which exhibited a respective response to ethylene and oxygen, while the extrinsic excitation of TiO 2 induced by visible light maybe only produced the free electrons but not free holes, resulting in only a response to oxygen. Furthermore, it was found that the visible-light enhanced conductivity maybe depend on the Ti–bonded hydroxyls (Ti–OH) at TiO 2 surface. With the removal of Ti–OH by increasing temperature, the visible light could not produce the photoconductivity of TiO 2 . It was proposed that Ti–OH groups act as the shallow trapped level to cause the extrinsic excitation of TiO 2 .
研究领域:
材料科学
·
半导体物理
·
传感器技术
·
光化学
·
表面科学
·
纳米材料
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2016
·
IF 4.803
Jing Lin,Lianshan Sun,Zhanyi Cao,Dongming Yin,Fei Liang,Yaoming Wu,Limin Wang
We describe our recent progress on a novel method to prepare Ti 1.4 V 0.6 Ni hydrogen storage alloy covered with nanostructured Co 3 O 4 by utilizing zelolitic imidazolate framework 67 (ZIF-67) as the template. Ti 1.4 V 0.6 Ni@C@Co 3 O 4 composite is prepared through a dopamine self-polymerization and a facile precipitation reaction with the subsequent thermal treatment. This specific composite structure combines the high conductivity of carbon together with the promising catalytic property of nanostructured Co 3 O 4 , therefore the enhanced electrochemical activity and stability are realized. As a result, Ti 1.4 V 0.6 Ni@C@Co 3 O 4 composite electrode possesses a capacity conservation rate of 56.1% after 300 charging/discharging cycles, remarkably larger than that of Ti 1.4 V 0.6 Ni (25.3%). Moreover, a study of the kinetics demonstrates that nanostructured Co 3 O 4 coating accelerates the charge-transfer reaction of the electrode. These results prove that coating with carbon and nanostructured Co 3 O 4 is a potential method for enhancing electrochemical hydrogen storage properties of hydrogen storage alloys.
研究领域:
材料科学
·
电化学
·
能源存储
·
金属氢化物电池
·
纳米材料
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2018
·Vol. 29
·期 23
·19614-19619
·
IF 2.324
Hu Yiwei,Chen Xinhang,Ren Xiaohui,Huang Zongyu,Qi Xiang,Zhong Jianxin
Tin disulfide (SnS 2 ) has been attracted intensive attention in the field of photoelectric conversion due to its appropriate band gap and glorious electronic mobility. The hexagon SnS 2 nanosheets has been successfully integrated through a facile one-pot hydrothermal method. SEM images, Raman spectra, atomic force microscope and X-ray diffraction patterns are measured to carry out to investigate the morphologies and microstructures of SnS 2 nanosheetsm, confirming a good crystallized SnS 2 . Then, the photochemical activity of as-prepared SnS 2 nanosheets were tested in the electrolyte of Na 2 SO 4 . Photoelectrochemical tests demonstrate that the photocurrent density of as-prepared hexagon SnS 2 nanosheets (1.66 µA/cm 2 at a light intensity of 140 mW/cm 2 ) is hugely increased with increasing light intensity. Furthermore, after 50 cycles, the photocurrent density does not change significantly, indicating that the as-prepared SnS 2 nanosheets possesses superior stabilities. The outstanding photocatalytic performances of SnS 2 nanosheets are not only resulted from its huge specific surface area, which can harvest more light and provide more active sites, but also attributed to its superior charge mobility, which can facilitate the separation photogenerated electron–hole pairs and the charge transfer between SnS 2 nanosheets and the electrode. The most important is that our work reveals the hexagonal SnS 2 nanosheets not only possess superior photoelectrochemical properties, but also have great potential applications in energy conversion and photodetector fields.
研究领域:
材料科学
·
光催化
·
能源转换
·
纳米材料
·
光电化学
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2021
·
IF 6.901
J. LUO,J.X. Liu,F.M. Xiao,L. Huang,W.C. Li,R.H. Tang,Q. Zhou,Y. Wang
In order to restrain the capacity decay of nickel-rich materials for lithium-ion batteries (LIBs) in advanced energy applications, a Ni-rich cathode (LiNi 0.88 Co 0.07 Al 0.05 O 2 , LANCA) with high-rate capability and cycle life was designed and prepared by coating γ-LiAlO 2 and doping Al 3+ on the surface and inside of the secondary particles, respectively. Specifically, the γ-LiAlO 2 -coated and Al 3+ -doped LANCA samples were synthesized by a simple strategy of pre-coating Ni 0.88 Co 0.07 Al 0.05 (OH) 2 , based on aluminum isopropoxide hydrolysis combined with a post-sintering lithiation process. With the γ-LiAlO 2 and Al 3+ , the capacity retention ratio of the cathode is tremendously improved from 61.7 to 83.6% at 1 C rate after 100 cycles. Even at a heavy current density of 10 C for the LANCA cathode, a high reversible capacity of 154.4 mA h g − 1 can be acquired, which amount to the 82.5% capacity retention at 0.2 C. Detailed morphology and structure observation shows that the side reaction at the electrolyte-cathode interface was suppressed, the structural degradation and intergranular cracking were suppressed, while the diffusion of Li + and conductivity were improved. Therefore, this ingenious structural design has certain reference significance for the development and commercialization of high-performance cathode materials for electric power.
研究领域:
材料科学
·
电化学
·
能源存储
·
无机化学
·
固态化学
✓ 已验证
DOI
高影响因子
MATERIALS LETTERS
·
2020
·
IF 3.204
Yun Zhang,Shihua Ding,Tianxiu Song,Yingchun Zhang
CoSnNb 2 O 8 ceramic with medium-permittivity was initially generated. Compositionally induced phase formation was identified by X-ray diffraction. Tetragonal rutile-type CoSnNb 2 O 8 was obtained from the reaction of SnO 2 with intermediate phase CoNb 2 O 6 . Both the dielectric constant ε r and quality factor Q × f initially increased with the sintering temperature, reaching the maxima at around 1225 °C, and declined thereafter. They were discussed based on the ionic polarizabilities and packing fraction, respectively. The temperature coefficient of resonant frequency τ f primarily depended on the Nb-site bond valence, as well as oxygen octahedra distortion. When sintered at 1225 °C, the CoSnNb 2 O 8 ceramic exhibited optimum properties with ε r = 31.8, Q × f = 43,000 GHz, and τ f = 35.01 ppm/°C.
研究领域:
材料科学
·
无机非金属材料
·
介电物理
·
功能陶瓷
·
微波材料
✓ 已验证
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2017
·
IF 6.395
Yongpeng Cui,Huanlei Wang,Nan Mao,Wenhua Yu,Jing Shi,Minghua Huang,Wei Liu,Shougang Chen,Xin Wang
The increasing demand for supercapacitors with high energy and power density has attracted extensive attention in designing advanced carbon materials with high accessible surface area, hierarchical porosity , and 2D/3D morphology. Here, we report a new approach to tune the morphology and structure of the nanocarbons by using methyl cellulose as the precursor. Due to the varying effect of different activating agents, the interconnected sheet-like carbon with a high surface area of up to 2285 m 2 g −1 and a thickness down to ∼4 nm can be obtained. These important characteristics make the nanocarbons demonstrate a high capacitance of 144 F g −1 at 1 A g −1 and 20 °C, and an excellent capacitance retention ratio of 64% at 100 A g −1 in ionic liquid . Because of the high fraction of meso/macropores for nanocarbons, an outstanding capacitance of 116 F g −1 can be achieved at 0 °C, with a high capacitance retention ratio of 39% at 100 A g −1 . A high energy of 16–17 and 9–10 W h kg −1 can be maintained at 20 and 0 °C when the supercapacitor is charged in less than 1s. The excellent electrochemical response of nanocarbons suggests that the proposed preparation process is promising for developing advanced carbon electrodes.
研究领域:
材料科学
·
电化学
·
纳米科技
·
能源存储
·
功能材料
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）