Journal of Materials Chemistry A
·
2016
·Vol. 4
·期 43
·16982-16991
·
IF 8.262
Chao Li,Tongfei Shi,Hideya Yoshitake,Hongyu Wang
The interactions between silicon particles and polymeric binders are a key factor during the course of manufacturing high-capacity Si anodes for lithium-ion batteries. Polymeric binders usually compensate for the volumetric over-changes of silicon particles, and then prevent electrode deformation while keeping the integrity of electron and ion pathways. This work explores an efficient synthesis method to directly anchor a reliable binder tightly on the surface of Si particles by in situ polymerization of an acrylic acid monomer in the mixing process of Si-based slurry. The resultant Si composite electrode possesses a highly elastic structure, which can provide a highly extensible space accommodating volume expansion/contraction of Si particles during lithiation/delithiation. Moreover, the cross-linked acrylic acid network results in a strong cohesive force between Si particles and auxiliary materials, such as conductive agent and copper foil. Accordingly, a satisfactory electrochemical performance of the Si anode can be gained, including a high initial coulombic efficiency of ∼73% and stable cycling performance (∼82% retention over 300 cycles at a current density of 4 A g−1). Such a novel and facile fabrication process represents an appealing method for manufacturing high-performance Si-based anodes using micron-sized Si particles with low cost.
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2016
·
IF 3.205
Weidong Chen,Guotao Wu,Teng He,Zhao Li,Zaiping Guo,Huakun Liu,Zhenguo Huang,Ping Chen
Octahydrotriborates are potential hydrogen storage materials and chemical vapor deposition precursors to boride films. Their syntheses have been quite challenging, however. In this paper, an improved facile route for the preparation of unsolvated sodium octahydrotriborate (NaB 3 H 8 ), which is an important precursor to other octahydrotriborates and derivatives, is reported. The key steps in the synthesis involve dispersing Na finely in inert media and preparing fresh tetrahydrofuran (THF)·BH 3 at room temperature . High purity unsolvated NaB 3 H 8 can be obtained in tens of grams or more in one batch, depending on the reactor size. Using NaB 3 H 8 as the precursor, sodium dodecaborate (Na 2 B 12 H 12 ) has been successfully synthesized. Both octahydrotriborates and dodecaborates have been observed as intermediates during the thermal dehydrogenation of borohydrides , and their facile syntheses would facilitate mechanistic studies on the hydrogen storage of borohydrides , among other potential applications.
✓ 已验证
产品关联
DOI
高影响因子
POWDER TECHNOLOGY
·
2017
·
IF 2.942
Jing Wu,Wenmao Tu,Yong Zhang,Binlin Guo,Shanshan Li,Yue Zhang,Yadong Wang,Mu Pan
PDA/GO-Si composite is synthesized and tested as anode material for lithium ion batteries . Silicon nanoparticles were first cooperated with graphite oxide (GO) and then embedded into a poly-dopamine (PDA) layer.PDA provides accommodation of volume change and protection to prevent the direct contact of the Si surface with electrolyte during charge/discharge cycling. GO acts as both volume change buffer and conductive support for the electrode. An initial discharge capacity of 2903 mAh•g − 1 was realized. A capacity of 1300 mAh•g − 1 was maintained after 450 cycles. The excellent capacity reversibility and long-term cycling stability of PDA/GO-Si was attributed to the intelligent structure and composition of the synthesized material.
✓ 已验证
产品关联
DOI
高影响因子
NANOTECHNOLOGY
·
2016
·Vol. 27
·期 32
·325702
·
IF 3.573
H L Hao,W S Wu,Y Zhang,L K Wu,W Z Shen
We present a detailed investigation into the origin of blue emission from colloidal silicon (Si) nanocrystals (NCs) fabricated by femtosecond laser ablation of Si powder in 1-hexene. High resolution transmission electron microscopy and Raman spectroscopy observations confirm that Si NCs with average size 2.7 nm are produced and well dispersed in 1-hexene. Fourier transform infrared spectrum and x-ray photoelectron spectra have been employed to reveal the passivation of Si NCs surfaces with organic molecules. On the basis of the structural characterization, UV–visible absorption, temperature-dependent photoluminescence (PL), time-resolved PL, and PL excitation spectra investigations, we deduce that room-temperature blue luminescence from colloidal Si NCs originates from the following two processes: (i) under illumination, excitons first form within colloidal Si NCs by direct transition at the X or Γ (Γ25 → Γ'2) point; (ii) and then some trapped excitons migrate to the surfaces of colloidal Si NCs and further recombine via the surface states associated with the Si–C or Si–C–H2 bonds.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 80
·76867-76873
·
IF 3.289
Yunfei Zhang,Bo Yang,Jinhong Fan,Luming Ma
In this study, abrasives-reinforced metal matrix composites (MMCs) with a microscale size synthesized by ball milling (BM) could achieve highly active and stable dechlorination efficiency for aqueous 2-chlorophenol (2-CP). The preparation process of this composite via BM was optimized to obtain a high degradation efficiency, especially for the effect of the abrasives including B4C, SiC, α-Al2O3, SiO2, Fe3O4 and Na2SO4. The results showed that the hardness of the abrasives in the Fe-based MMCs was closely related with their dechlorination performance. Subsequently, the optimal abrasive, i.e. SiO2 was further investigated for its proper milling conditions with zero-valent iron (ZVI) particles including optimal SiO2 size, SiO2 loading, milling time, and the dosage of the process control agent (PCA). Additionally, the influence of other metal categories including Al and Si was also investigated for dechlorination; and their low reaction efficiencies were closely related with their passivating film. Finally, the longevity test suggested that the decreased reactivity of the SiO2–Fe MMC during the storage in air could be recovered when consecutively used, mainly due to the promoting effects of the inherent structure of SiO2–Fe MMC with the Fe/C and Fe/SiO2 interfaces, as well as the effective regeneration of the reactive sites by continuous iron dissolution.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2017
·
IF 3.454
Y.L. Zhuang,T.S. Lin,S.J. Wang,P. He,D.P. Sekulic,D.C. Jia
The Ti 22 Si 78 (wt.%) braze was used to bond porous BN/Si 3 N 4 ceramic. The results revealed that the joint strength was low. In order to improve the joint strength, a carbon coated modification of the porous BN/Si 3 N 4 substrate, achieved by the pyrolysis of phenol-formaldehyde resin was suggested. The thickness of carbon layer was controlled by the volume ratio of phenol-formaldehyde resin and methyl alcohol (R/M). The effect of the carbon layer on the microstructure and mechanical properties of the joint was examined. It was established that the maximum joint strength was achieved at the level of 80 MPa (as opposed to the uncoated joint with only 30 MPa) when R/M was 1:2, at the given brazing temperature. The improvement of the joint strength is attributed mainly to the formation of a SiC infiltration reaction layer, a significant population of SiC nanowires, as well as TiN 0.7 C 0.3 and TiB 2 particles.
✓ 已验证
产品关联
DOI
高影响因子
Nanomaterials
·
2017
·Vol. 7
·期 10
·317
·
IF 3.553
Rong Guo,Tifeng Jiao,Ruirui Xing,Yan Chen,Wanchun Guo,Jingxin Zhou,Lexin Zhang,Qiuming Peng
Gold nanoparticles (AuNPs) have attracted widespread attention for their excellent catalytic activity, as well as their unusual physical and chemical properties. The main challenges come from the agglomeration and time-consuming separation of gold nanoparticles, which have greatly baffled the development and application in liquid phase selective reduction. To solve these problems, we propose the preparation of polyvinyl alcohol(PVA)/poly(acrylic acid)(PAA)/Fe3O4nanocomposites with loaded AuNPs. The obtained PVA/PAA/Fe3O4composite membrane by electrospinning demonstrated high structural stability, a large specific surface area, and more active sites, which is conducive to promoting good dispersion of AuNPs on membrane surfaces. The subsequently prepared PVA/PAA/Fe3O4@AuNPs nanocomposites exhibited satisfactory nanostructures, robust thermal stability, and a favorable magnetic response for recycling. In addition, the PVA/PAA/Fe3O4@AuNPs nanocomposites showed a remarkable catalytic capacity in the catalytic reduction of p-nitrophenol and 2-nitroaniline solutions. In addition, the regeneration studies toward p-nitrophenol for different consecutive cycles demonstrate that the as-prepared PVA/PAA/Fe3O4@AuNPs nanocomposites have outstanding stability and recycling in catalytic reduction.Keywords:Au nanoparticles;composite materials;catalytic reduction;electrospinning;p-nitrophenol
✓ 已验证
产品关联
DOI
PubMed
高影响因子
WEAR
·
2015
·
IF 1.913
Z.C. Lu,M.Q. Zeng,Y. Gao,J.Q. Xing,M. Zhu
In this work, an attempt was made to further promote the wear and friction behavior of dual-scale structured Al–12 wt% Sn bearing alloys by coupling with a nano-Si@Sn composite. A so-called tri-modal Al–Sn–Si (denoted as CG-30 Si-containing alloy), which exhibited increased bulk hardness and improved distribution and refinement of the Sn phase, was produced by combining mechanical alloying and conventional powder sintering. The wear performance of the Si-containing and Si-free alloys was differentiated by performing both block-on-ring and ball-on-disk testing. Moreover, the addition of nano-Si@Sn composites to the dual-scale Al–Sn matrix resulted in significant reductions of the friction coefficient and wear volume. These improvements in wear behavior stemmed from the polishing effect of fine Si particles on the counterface , and Sn-rich clusters that acted as lubricants on the worn surface; together, the polishing effect and lubrication led to the formation of a smooth tribolayer, and hence, a decrease in the tendency for abrasive wear . Abrasive wear was also reduced by an increase in the alloy hardness with the addition of Si. As such, Sn-phase modification via Si addition constitutes a promising method for preparing self-lubricating Al-based alloys.
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry A
·
2015
·Vol. 3
·期 20
·10999-11005
·
IF 7.443
Xunfu Zhou,Qiongzhi Gao,Xin Li,Yingju Liu,Shengsen Zhang,Yueping Fang,Jun Li
Herein, for the first time, ultra-thin SiC nanoparticles or ultra-thin layer covered graphene nanosheets were successfully prepared via using a facile in situ vapor–solid reaction. The samples were characterized by X-ray diffraction, UV-visible spectroscopy, photoluminescence spectra analysis, Raman spectra, transient photocurrent responses and transmission electron microscopy. The photocatalytic activities were also evaluated by H2 evolution from pure water or water containing Na2S as an electron donor. The resulting SiC–graphene hybrids show enhanced photocatalytic H2-evolution activities in the presence of an electron donor. Especially, the graphene nanosheet and SiC nanocrystal hybrids show the highest photocatalytic activity in H2 production under visible light, which is about 10 times higher than that of the SiC nanocrystals. The enhanced activities of the SiC–graphene hybrids can be attributed to their 2D nanosheet structures, large surface area, enhanced visible-light absorption and rapid interfacial charge transfer from SiC to graphene. Our results can provide an effective approach to synthesize graphene-based heterogeneous nanocomposites for a wide variety of potential applications in solar energy conversion and storage, separation, and purification processes.
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2017
·
IF 7.504
Wenhao Fan,Shaoping Chen,Bo Zeng,Qiang Zhang,Qingsen Meng,Wenxian Wang,Zuhair A. Munir
Solid solutions of Mg2Si0.6Sn0.4–xBix with 0 ≤ x ≤ 0.03 were prepared by a one-step synthesis and consolidation method, using MgH2 as a starting material. The thermoelectric properties of these samples were evaluated over the temperature range 300–775 K. Figure of merit, zT, values were determined over this range for all compositions and found to increase with temperature reaching a value of 1.36 at 775 K for samples with x = 0.02. Examination of the components of the total thermal conductivity showed that the bipolar thermal conductivity is suppressed by an increase in the band gap, resulting from solid solution formation, and by low minority carrier mobility. The suppression of the bipolar thermal conductivity is believed to be the consequence of charged grain boundaries.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SURFACE & COATINGS TECHNOLOGY
·
2017
·
IF 2.589
K.Q. Song,Z.C. Lu,M. Zhu,R.Z. Hu,M.Q. Zeng
Nanocomposite Al–Sn-based bearing alloys produced by mechanical alloying (MA) exhibit high hardness; however, their poor sintering density and ductility limit their wide spread application. Here, we present a strategy to produce a dual-scale structure in an Al–Sn–Si alloy consisting of coarse and ultrafine grains through a combination of conventional powder sintering and thermomechanical treatment . We found that severe deformation and the presence of an Al–Si eutectic mixture for sample induced abnormal grain growth of Al to create the dual-scale Al–Sn–Si alloy through annealing treatment. An optimum matching of ductility and strength , and optimum wear performance were achieved at annealing temperatures of 500 and 550 °C. Detailed investigation of the wear mechanism revealed that the combination of high strength and high ductility provided by the dual-scale structure is a key factor for the improvement of the wear properties.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2024
·
IF 4.1
Rui Zhang,Jianxun Zhao,Wanqiang Liu,Lianshan Sun,Qingcheng Liang,Peng Chen,Xinwei Wang
Mechanical alloying is used to prepare Co 0.9 Cu 0.1 Si hydrogen storage alloy. Coral-like polyaniline (PANI) and NiO nanoparticles (NiO NPs) are synthesized separately. In order to improve the electrochemical properties of the alloy, polyaniline, NiO NPs and graphene oxide (GO) are doped into the alloy via mechanical alloying to form a composite. The composite material doped with PANI, NiO NPs and GO ultimately demonstrates superior discharge capability compared to the pristine alloy, establishing it as the most high-performing among all samples. The sample doped with both PANI or NiO NPs and GO exhibited superior discharge capacity and HRD performance compared to the sample containing only GO. The Co 0.9 Cu 0.1 Si + PANI/NiO NPs/GO electrode not only demonstrates a remarkable maximum discharge capacity of 590.82 mAh/g, but it also boasts an impressive highest exchange current density of 180.5 mA/g, alongside a notable cycle stability of 61.1 %. The enhancement of electrochemical activity and kinetic performance in alloys is attributed to the synergistic effect exerted by PANI, NiO NPs and GO. GO itself has a high specific surface area and good conductivity, which is conducive to the transfer of hydrogen inside the alloy and enhance the hydrogen storage performance of the alloy. Polyaniline participate in the reversible redox reaction and remain stable during the charge/discharge cycle, which promoted the surface anodizing process of the alloy. The NiO NPs catalyst can effectively weaken the O H bond, facilitating the dissociation of adsorbed water. These factors work together to significantly improve the overall electrochemical hydrogen storage performance of the alloy.
✓ 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）