A rapid-heating method in the absence of electric/magnetic field was achieved by introducing a self-propagating-combustion （SHS） as heating source. The effect of heating rate on the alumina grain growth was explored...
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A rapid-heating method in the absence of electric/magnetic field was achieved by introducing a self-propagating-combustion （SHS） as heating source. The effect of heating rate on the alumina grain growth was explored based on this rapid-heating method. Comparing with the alumina prepared by two different heating ratios （greater than 1 000 ℃/min in SItS and about 50 ℃/min in common pressureless sintering furnace）, it was revealed that the rapid heating could promote the grain growth greatly without pressure during sintering. However, if a pressure was applied simultaneously, the grain growth would be almost completely restrained. Since these observations are quite different from the expectation, a new grain growth model was proposed.
A series of new microwave dielectric ceramics Ba3-nLa1+nTinNb3-nO12 (n=0,1,2) were prepared in the BaO-La2O3-TiO2-Nb2O5 system by high temperature solid-state reaction route. The phase and structure of the ceramics we...
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A series of new microwave dielectric ceramics Ba3-nLa1+nTinNb3-nO12 (n=0,1,2) were prepared in the BaO-La2O3-TiO2-Nb2O5 system by high temperature solid-state reaction route. The phase and structure of the ceramics were characterized by X-ray diffraction, scanning electron microscope, and microwave dielectric properties measurements. These samples were identified as single phase and adopted A4B3O12-type cation-deficient hexagonal perovskite structure, which can be described as consisting of identical perovskite-like blocks, three corner-sharing BO6 octahedra thick, separated by layers of vacant octahedral. These ceramics have high dielectric constants in the range of 48-42, high quality factors (Q×f) up to 38 000 GHz, and low temperature coefficient of resonant frequencies (τf) in the range of (-40-+6)×10-6℃-1. With increasing content of La and Ti, the dielectric constants slightly decrease butτf gradually increases.
The unsatisfactory conductivity and large volume variation severely handicap the application of SnO2in sodium-ion batteries（SIBs）. Herein, we design unique three-layer structured SnO2@C@TiO2hollow spheres to tackle ...
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The unsatisfactory conductivity and large volume variation severely handicap the application of SnO2in sodium-ion batteries（SIBs）. Herein, we design unique three-layer structured SnO2@C@TiO2hollow spheres to tackle the above-mentioned issues. The hollow cavity affords empty space to accommodate the volume variation of SnO2, while the C and TiO2protecting shells strengthen the structural integrity and enhances the electrical conductivity. As a result, the three-layer structured SnO2@C@TiO2hollow spheres demonstrate enhanced Na storage performances. The SnO2@C@TiO2manifests a reversible capacity two times to that of pristine SnO2hollow spheres. In addition, Ex situ XRD reveals highly reversible alloying and conversion reactions in SnO2@C@TiO2hollow spheres. This study suggests the introduction of a hollow cavity and robust protecting shells is a promising strategy for constructing SIB anode materials.
Lithium metal is a promising anode material owing to its very low electrochemical potential and ultrahigh specific ***,the growth of lithium dendrites could result in a short lifespan,low coulombic efficiency,and pote...
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Lithium metal is a promising anode material owing to its very low electrochemical potential and ultrahigh specific ***,the growth of lithium dendrites could result in a short lifespan,low coulombic efficiency,and potential safety hazards during the progress of lithium plating/*** factors drastically hinder its application in lithium metal *** review focuses on the use of three dimensional(3D)porous host frameworks to improve Li plating/stripping behaviors,accommodate the change in volume,and suppress or block lithium dendrite *** 3D porous frameworks,including the conductive carbon-based,metal-based,and lithiophilic inorganic-compound frameworks are introduced and summarized in *** particular functions,relative developments,and optimized strategies of various 3D porous frameworks for lithium deposition/dissolution behaviors are ***,the challenges and promising developments in the field of Li metal anodes will be discussed at the end of this review.
Under the vision of 'carbon peaking and carbon neutrality',the global energy system is facing a deep *** a clean energy with the potential to achieve zero carbon emissions,hydrogen energy will undoubtedly play...
Under the vision of 'carbon peaking and carbon neutrality',the global energy system is facing a deep *** a clean energy with the potential to achieve zero carbon emissions,hydrogen energy will undoubtedly play an important ***-energy-driven photo catalytic reactions can decompose water to produce hydrogen and reduce carbon dioxide to produce solar fuels.
ZnO hexagonal prism crystals were synthesized from ZnO powders by microwave heating in a short time （within 20 min） without any metal catalyst or transport agent. Zinc oxide raw materials were made by evaporating fr...
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ZnO hexagonal prism crystals were synthesized from ZnO powders by microwave heating in a short time （within 20 min） without any metal catalyst or transport agent. Zinc oxide raw materials were made by evaporating from the high-temperature zone in an enclosure atmosphere and crystals were grown on the self-source substrate. The inherent asymmetry in microwave heating provides the temperature gradient for crystal growth. Substrate and temperature distribution in the oven show significant effects on the growth of the ZnO crystal. The morphologies demonstrate that these samples are pure hexagonal prism crystals with maximum 80 lain in diameter and 600 lure in length, which possess a well faceted end and side surface. X-ray diffraction （XRD） reveals that these samples are pure crystals. The photoluminescence （PL） exhibits strong ultraviolet emission at room temperature, indicating potential applications for short-wave light-emitting photonic devices.
High-performance anode is hurdle for on-chip planar microsupercapacitor(MSC).Polypyrrole(PPy)is a highly attractive pseudocapacitive material,but its low cycling stability,and low adhesion with current collector hinde...
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High-performance anode is hurdle for on-chip planar microsupercapacitor(MSC).Polypyrrole(PPy)is a highly attractive pseudocapacitive material,but its low cycling stability,and low adhesion with current collector hinder its *** we propose one-prong generic strategy to boost the cycling stability of *** our strategy,the electrochemical deposition of multilayered reduced graphene oxide(rGO)on micropatterned Au is utilized,and the resultant rGO@Au pattern is then used for growing highly porous PPy nanostructures by facile electrochemical *** fabricated PPy anode on rGO@Au has quasi rectangular cyclic voltammetry curves up to-0.7 V and exceptional cycling stability,retaining82%of capacitance after 10,000 charge/discharge cycles in 2 M KCl *** outstanding reliability of PPy on rGO@Au is due to the flexibility of rGO,accommodating structural pulverization and providing a promising background for the nucleation of highly porous ***,an all-polymer based asymmetric aqueous MSC(AMSC)is constructed with PPy anode and PEDOT cathode,which exhibited excellent electrochemical performance compared with conventional symmetric MSCs based on conducting *** constructed AMSC delivered a maximum areal capacitance of 15.9 m F cm^-2(99.3 F cm^-3),high specific energy and power densities of 4.3μWh cm^-2(27.03 mWh cm^-3)and 0.36 W cm^-2(0.68 W cm^-3)at 1.4 V,*** enhanced electrochemical performances can be illustrated by nucleation mechanism,in which surface topology of r GO generates a promising background for nucleation and electrochemical growth of nanoporous pseudocapacitive conducting polymers with superior interfacial contact and improved surface area.
The objective of this paper is to understand the flow mechanism through visualization experiments and discuss theinfluence of process parameters on mold filling process. A 2D leakage flow model is developed to simulat...
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The objective of this paper is to understand the flow mechanism through visualization experiments and discuss theinfluence of process parameters on mold filling process. A 2D leakage flow model is developed to simulate the moldingprocess, and the simulation results show good agreement with experiments.
Designing highly efficient and stable photocatalysts is of vital importance for solar-to-fuel conversion,as a potential strategy to address the concerns of global energy crisis and environmental *** development of nov...
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Designing highly efficient and stable photocatalysts is of vital importance for solar-to-fuel conversion,as a potential strategy to address the concerns of global energy crisis and environmental *** development of novel photocatalytic materials is desirable to overcome those shortcomings of traditional semiconductor photocatalysts.
In this work,homogeneous Ni0.33Co0.67Se hollow nanoprisms were synthesized successfully in virtue of Kirkendall *** is the first time for bimetallic Ni-Co compounds Ni0.33Co0.67Se to be used in lithium-ion batteries (...
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In this work,homogeneous Ni0.33Co0.67Se hollow nanoprisms were synthesized successfully in virtue of Kirkendall *** is the first time for bimetallic Ni-Co compounds Ni0.33Co0.67Se to be used in lithium-ion batteries (LIBs).Impressively,the Ni0.33Co0.67Se hollow nanoprisms show superior specific capacity (1,575 mAh/g at the current density of 100 mA/g) and outstanding rate performance (850 mAh/g at 2,000 mA/g) as anode material for *** work proves the potential of bimetallic chalcogenide compounds as high performance anode materials for LIBs.
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