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
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
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
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
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
CHEMISTRY OF MATERIALS
·
2017
·
IF 9.466
Hongning Chen,Nien-Chu Lai,Yi-Chun Lu
Nonaqueous redox flow battery (RFB) is a promising technology to improve the energy density of RFBs for both stationary grid energy storage and electric vehicle applications. Despite tremendous advancement made in high-capacity flow posolyte, lithium metal has been dominantly exploited as a nonflowable counter electrode in reported lithium-based RFBs to date due to the lack of efficient and high-capacity flow negolyte. Here, we report a silicon–carbon nanocomposite semi-solid negolyte, achieving a high reversible capacity (>1200 mAh g–1) and stable cycle life (>100 cycles). A facile process of incipient wetness impregnation followed by polymerization/carbonization is developed to synthesize monodispersed Si–C nanocomposite with ultrathin graphitic carbon coating. Exploiting Si–C nanocomposite as the negolyte effectively suppresses the volume change of Si particles and enhances the electrical conductivity of the negolyte. Coupling with highly concentrated LiI (5.0 M), we demonstrate the first lithium metal-free Si-based negolyte in a full all-flow cell configuration with a stable cycle life (>60 cycles), high Coulombic efficiency (>90%), and the highest full cell voltage (3.0 V) reported for Li metal-free RFBs. Our successful demonstration of lithium metal-free all-flow battery highlights the promising potential of Si-based negolyte to replace lithium metal for high-energy-density RFBs.
✓ 已验证
产品关联
DOI
高影响因子
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
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
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 POWER SOURCES
·
2025
·
IF 7.9
Haiyan Guo,Lingbin Liu,Yuxiu Yu,Qiang Zhang,Qing Chang,Yaodong Liu
Binders play a vital role in silicon-based anode materials. In this study, we design and synthesize a series of silicon-based anode binders by incorporating functional monomers such as Diaminobenzoic acid (DABA), Aminopropyl terminated polydimethylsiloxane (PDMS) and 4,4′-diphenyl ether dianhydride (ODPA) into polyimide (PI) backbones. The goal is to develop binders with a balance of rigidity and flexibility to improve the electrochemical performance of silicon anodes in lithium-ion batteries. It is found that the chemical structure of the binder affects the swelling rate, bond strength and rigidity, which thereby impacts the electrochemical performances of silicon anode. The incorporation of (PDMS) enhances the binder's flexibility, which effectively accommodates the volume expansion of silicon during cycling, thereby improving cycling stability. However, excessive PDMS content leads to increased swelling rates and weakened adhesion, negatively affecting the formation and stability of the solid electrolyte interphase (SEI) layer and reducing first Coulombic efficiency (ICE). The co-polymerization of 1,3-bis(aminopropyl) tetramethyldisiloxane (NH 2 -DS) reduces the binder's solubility, resulting in improved ICE. Among the binders tested, Si@ODPA-NH 2 -DS-DABA exhibits the best cycling performance, has a specific capacity of 1690.2 mAh g −1 after 200 cycles at 0.2 C, due to its optimal rigid-flexible ratio, lower swelling rate, and stronger adhesion to the electrode. The synergistic effect of rigid benzene rings, imide bonds, and flexible ether and Si-O-Si units provide high strength, toughness, and adhesion. This study provides valuable insights into the design of silicon anode binders, demonstrating that a careful balance of binder flexibility, swelling rate, and adhesive strength is essential for achieving superior electrochemical performance and long-term cycling stability.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
·
2024
·
IF 4.3
Jianxun Zhao,Wenhao Fan,Wanqiang Liu,Lianshan Sun,Yuhai Wang,Heng Liu,Peng Chen,Qingcheng Liang,Yong Cheng,Xinwei Wang
The Co 0.9 Cu 0.1 Si alloy was prepared using the mechanical alloying method, while CeO 2 and Ni-CeO 2 were synthesized through the hydrothermal method. Various mass ratios of CeO 2 and Ni-CeO 2 were incorporated into the Co 0.9 Cu 0.1 Si alloy via the mechanical alloying process. The electrochemical test results demonstrated a significant enhancement in hydrogen storage performance compared to that of the original Co 0.9 Cu 0.1 Si alloy. In our experiment, the samples with identical doping ratios revealed that the composite material doped with Ni-CeO 2 exhibited superior electrochemical hydrogen storage performance compared to its counterpart solely doped with CeO 2 .When Ni-CeO 2 was doped in the composite material at a ratio of 20:1, the sample demonstrated exceptional electrochemical hydrogen storage performance. At a discharge current of 25 mA/g, the discharge capacity reached 606.7 mAh/g, and after 50 cycles, the capacity retention rate was measured at 63.4%. Furthermore, its corrosion resistance and exchange current density surpassed those of other samples. The multifarious origins underlying these outcomes are rooted in a multitude of factors. Primarily, nickel engenders this phenomenon through its provision of high specific capacitance, exceptional reversibility, and enhanced electrical conductivity. Additionally, the introduction of nickel into the CeO 2 lattice creates vacancies that enhance hydrogen adsorption and facilitate charge transfer processes. Furthermore, CeO 2 and Ni-CeO 2 form the protective layer for the alloy, preventing dissolution of its constituents on the surface while improving resistance against fragmentation and corrosion. The findings of this investigation support the idea that incorporating transition metal oxides doped with metallic impurities into hydrogen storage alloys can improve their electrochemical performance and kinetic attributes, while also strengthening their resistance to corrosive influences.
✓ 已验证
产品关联
DOI
高影响因子
International Journal of Applied Ceramic Technology
·
2024
·
IF 1.8
Ruibin Liu,Yuhong Chen,Zhengxiang Chen,Wanxiu Hai,Meiling Liu
Particle grading is a reliable method to improve mechanical properties of reaction-bonded silicon carbide (RBSC) ceramics. This work aims to explore the effects of particle grading on thermal and mechanical characteristics of RBSC ceramics. Results showed that the powder grading enabled to increase sintering density of silicon carbide (SiC) ceramics. The use of large particle SiC powder in grading led to a 28% increase in thermal conductivity but a 22% decrease in bending strength. Meanwhile, the addition of finer SiC powder exerted minimal effect on thermal conductivity but noticeably increased bending strength by 10%. Therefore, properly adjusting particle size in grading allows for the control of residual Si content and microstructure, thereby simultaneously increasing thermal conductivity and bending strength of the material.
✓ 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）