首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到11条相似文献,搜索用时 0 毫秒
1.
A facile one-step strategy involving the reaction of antimony chloride with thioacetamide at room temperature is successfully developed for the synthesis of strongly coupled amorphous Sb2S3 spheres and carbon nanotubes (CNTs). Benefiting from the unique amorphous structure and its strongly coupled effect with the conductive network of CNTs, this hybrid electrode (Sb2S3@CNTs) exhibits remarkable sodium and lithium storage properties with high capacity, good cyclability, and prominent rate capability. For sodium storage, a high capacity of 814 mAh·g?1 at 50 mA·g?1 is delivered by the electrode, and a capacity of 732 mAh·g?1 can still be obtained after 110 cycles. Even up to 2000 mA·g?1, a specific capacity of 584 mAh·g?1 can be achieved. For lithium storage, the electrode exhibits high capacities of 1136 and 704 mAh·g?1 at 100 and 2000 mA·g?1, respectively. Moreover, the cell holds a capacity of 1104 mAh·g?1 under 100 mA·g?1 over 110 cycles. Simple preparation and remarkable electrochemical properties make the Sb2S3@CNTs electrode a promising anode for both sodium-ion (SIBs) and lithium-ion batteries (LIBs).  相似文献   

2.
Monoclinic SrAl2Si2O8 ceramics for Sr immobilization were prepared by a liquid-phase sintering method. The sintering temperature, mineral phase composition, microstructure, flexural strength, bulk density, and Sr ion leaching characteristics of the SrAl2Si2O8 ceramics were investigated. A crystalline monoclinic SrAl2Si2O8 phase formed through liquid-phase sintering at 1223 K. The introduction of four flux agents (B2O3, CaO·2B2O3, SrO·2B2O3, and BaO·2B2O3) to the SrAl2Si2O8 ceramics not only reduced the densification temperature and decreased the volatilization of Sr during high-temperature sintering but also impacted the mechanical properties of the ceramics. Product consistency tests showed that the leaching concentration of Sr ions in the sample with flux agent B2O3 was the lowest, whereas that of Sr ions in the sample with flux agent BaO·2B2O3 was the highest. These results show that the leaching concentration of Sr ions depends largely on the amorphous phase in the ceramics. Meanwhile, the formation of mineral analog ceramics containing Sr is an important factor to improve Sr immobilization.  相似文献   

3.
A near eutectic Al?12.6Si alloy was developed with 0.0wt%, 2.0wt%, 4.0wt%, and 6.0wt% Al?5Ti?1B master alloy. The microstructural morphology, hardness, tensile strength, elongation, and fracture behaviour of the alloys were studied. The unmodified Al?12.6Si alloy has an irregular needle and plate-like eutectic silicon (ESi) and coarse polygonal primary silicon (PSi) particles in the matrix-like α-Al phase. The PSi, ESi, and α-Al morphology and volume fraction were changed due to the addition of the Al?5Ti?1B master alloy. The hardness, UTS, and elongation improved due to the microstructural modification. Nano-sized in-situ Al3Ti particles and ex-situ TiB2 particles caused the microstructural modification. The fracture images of the developed alloys exhibit a ductile and brittle mode of fracture at the same time. The Al?5Ti?1B modified alloys have a more ductile mode of fracture and more dimples compared to the unmodified alloy.  相似文献   

4.
The oxidation of oxygen ions and the generation of an anode effect at a low oxygen content of 150 mg/kg were discussed in this paper. Cyclic voltammetry and square-wave voltammetry tests were conducted to explore the anodic processes of LiF–NdF3 melt after a lengthy period of pre-electrolysis purification at 1000°C (during which the oxygen content reduced from 413 to 150 mg/kg). The oxidation process of oxygen ions was found to have two stages: oxidation product adsorption and CO/CO2 gas evolution. The adsorption stage was controlled by diffusion, whereas the gas evolution was controlled by the electrochemical reaction. In comparison with oxygen content of 413 mg/kg, the decrease in the amplitude of the current at low oxygen content of 150 mg/kg was much gentler during the forward scanning process when the anode effect occurred. Fluorine-ion oxidation peaks that occurred at about 4.2 V vs. Li/Li+ could be clearly observed in the reverse scanning processes, in which fluorine ions were oxidized and perfluorocarbons were produced, which resulted in an anode effect.  相似文献   

5.
Wood-based panels containing urea-formaldehyde resin result in the long-term release of formaldehyde and threaten human health. In this study, inorganic aluminosilicate coatings prepared by combining metakaolin, silica fume, NaOH, and H2O were applied to the surfaces of wood-based panels to obstruct formaldehyde release. The Si/Al, Na/Al, and H2O/Na2O molar ratios of the coatings were regulated to investigate their effects on the structure and formaldehyde-resistant barrier properties of coatings. Results showed that the cracks in the coatings gradually disappeared and the formaldehyde resistance rates of the barrier increased as the Si/Al molar ratio was increased from 1.6 to 2.2. This value also increased as the Na/Al molar ratio was increased from 0.9 to 1.2 because of the improvement of the degree of polymerization. As the H2O/Na2O molar ratio was increased from 12 to 15, the thickness of the dry film decreased gradually and led to the reduction in the formaldehyde resistance rate. When the Si/Al, Na/Al, and H2O/Na2O molar ratios were 2.2, 1.2, and 12, respectively, the inorganic aluminosilicate coating showed good performance as a formaldehyde-resistant barrier and its formaldehyde resistance rate could reach up to 83.2%.  相似文献   

6.
Pt/CeO2–C catalysts with CeO2 pre-calcined at 300–600°C were synthesized by combining hydrothermal calcination and wet impregnation. The effects of the pre-calcined CeO2 on the performance of Pt/CeO2–C catalysts in methanol oxidation were investigated. The Pt/CeO2–C catalysts with pre-calcined CeO2 at 300–600°C showed an average particle size of 2.6–2.9 nm and exhibited better methanol electro-oxidation catalytic activity than the commercial Pt/C catalyst. In specific, the Pt/CeO2–C catalysts with pre-calcined CeO2 at 400°C displayed the highest electrochemical surface area value of 68.14 m2·g?1 and If/Ib ratio (the ratio of the forward scanning peak current density (If) and the backward scanning peak current density (Ib)) of 1.26, which are considerably larger than those (53.23 m2·g?1 and 0.79, respectively) of the commercial Pt/C catalyst, implying greatly enhanced CO tolerance.  相似文献   

7.
We report the electrochemical performance of Ni(OH)2 on a gas diffusion layer (GDL). The Ni(OH)2 working electrode was successfully prepared via a simple method, and its electrochemical performance in 1 M NaOH electrolyte was investigated. The electrochemical results showed that the Ni(OH)2/GDL provided the maximum specific capacitance value (418.11 F·g?1) at 1 A·g?1. Furthermore, the Ni(OH)2 electrode delivered a high specific energy of 17.25 Wh·kg?1 at a specific power of 272.5 W·kg?1 and retained about 81% of the capacitance after 1000 cycles of galvanostatic charge–discharge (GCD) measurements. The results of scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS) revealed the occurrence of sodium deposition after long-time cycling, which caused the reduction in the specific capacitance. This study results suggest that the light-weight GDL, which can help overcome the problem of the oxide layer on metal–foam substrates, is a promising current collector to be used with Ni-based electroactive materials for energy storage applications.  相似文献   

8.
We successfully constructed TiO2-pillared multilayer graphene nanocomposites (T-MLGs) via a facile method as follows: dodecanediamine pre-pillaring, ion exchange (Ti4+ pillaring), and interlayer in-situ formation of TiO2 by hydrothermal method. TiO2 nanoparticles were distributed uniformly on the graphene interlayer. The special structure combined the advantages of graphene and TiO2 nanoparticles. As a result, T-MLGs with 64.3wt% TiO2 showed the optimum photodegradation rate and adsorption capabilities toward ciprofloxacin. The photodegradation rate of T-MLGs with 64.3wt% TiO2 was 78% under light-emitting diode light irradiation for 150 min. Meanwhile, the pseudo-first-order rate constant of T-MLGs with 64.3wt% TiO2 was 3.89 times than that of pristine TiO2. The composites also exhibited high stability and reusability after five consecutive photocatalytic tests. This work provides a facile method to synthesize semiconductor-pillared graphene nanocomposites by replacing TiO2 nanoparticles with other nanoparticles and a feasible means for sustainable utilization of photocatalysts in wastewater control.  相似文献   

9.
To improve the sulfur loading capacity of lithium-sulfur batteries (Li–S batteries) cathode and avoid the inevitable “shuttle effect”, hollow N doped carbon coated CoO/SnO2 (CoO/SnO2@NC) composite has been designed and prepared by a hydrothermal-calcination method. The specific surface area of CoO/SnO2@NC composite is 85.464 m2·g–1, and the pore volume is 0.1189 cm3·g–1. The hollow core-shell structure as a carrier has a sulfur loading amount of 66.10%. The initial specific capacity of the assembled Li–S batteries is 395.7 mAh·g–1 at 0.2 C, which maintains 302.7 mAh·g–1 after 400 cycles. When the rate increases to 2.5 C, the specific capacity still has 221.2 mAh·g–1. The excellent lithium storage performance is attributed to the core-shell structure with high specific surface area and porosity. This structure effectively increases the sulfur loading, enhances the chemical adsorption of lithium polysulfides, and reduces direct contact between CoO/SnO2 and the electrolyte.  相似文献   

10.
In this study, we prepared Ti/IrO2–ZrO2 electrodes with different ZrO2 contents using zirconium-n-butoxide (C16H36O4Zr) and chloroiridic acid (H2IrCl6) via a sol–gel route. To explore the effect of ZrO2 content on the surface properties and electrochemical behavior of electrodes, we performed physical characterizations and electrochemical measurements. The obtained results revealed that the binary oxide coating was composed of rutile IrO2, amorphous ZrO2, and an IrO2–ZrO2 solid solution. The IrO2–ZrO2 binary oxide coatings exhibited cracked structures with flat regions. A slight incorporation of ZrO2 promoted the crystallization of the active component IrO2. However, the crystallization of IrO2 was hindered when the added ZrO2 content was greater than 30at%. The appropriate incorporation of ZrO2 enhanced the electrocatalytic performance of the pure IrO2 coating. The Ti/70at%IrO2–30at%ZrO2 electrode, with its large active surface area, improved electrocatalytic activity, long service lifetime, and especially, lower cost, is the most effective for promoting oxygen evolution in sulfuric acid solution.  相似文献   

11.
This study aims to discover the stress-state dependence of the dynamic strain aging (DSA) effect on the deformation and fracture behavior of high-strength dual-phase (DP) steel at different deformation temperatures (25–400°C) and reveal the damage mechanisms under these various configurations. To achieve different stress states, predesigned specimens with different geometric features were used. Scanning electron microscopy was applied to analyze the fracture modes (e.g., dimple or shear mode) and underlying damage mechanism of the investigated material. DSA is present in this DP steel, showing the Portevin–Le Chatelier (PLC) effect with serrated flow behavior, thermal hardening, and blue brittleness phenomena. Results show that the stress state contributes distinctly to the DSA effect in terms of the magnitude of thermal hardening and the pattern of blue brittleness. Either low stress triaxiality or Lode angle parameter promotes DSA-induced blue brittleness. Accordingly, the damage mechanisms also show dependence on the stress states in conjunction with the DSA effect.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号