Inspired by structures of natural shells,zirconia-carbon nanocomposites were obtained by using natural chitin from shrimp shells as templates via the sol-gel route in this *** was dispersed in the water and chelated w...
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Inspired by structures of natural shells,zirconia-carbon nanocomposites were obtained by using natural chitin from shrimp shells as templates via the sol-gel route in this *** was dispersed in the water and chelated with the zirconia precursors by *** a heat treatment for carbonization,nacre-like structures of carbon-zirconia nanocomposites were successfully *** to the toughening mechanism of tetragonal zirconia,the mechanical properties of carbon-zirconia composites are further *** as-received zirconia/carbon nanocomposite with best mechanical property has a hardness of 5.88GPa and an elastic modulus of 80.6 GPa,which is even stronger than natural *** work might facilitate a versatile platform for developing green nanocomposites with reasonably good mechanical properties.
Ceramic hollow spheres have great potential for deep-sea ***,the irregularity of the conventional molding process,among other reasons,results in low wall thickness uniformity of hollow *** solve this problem,in this w...
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Ceramic hollow spheres have great potential for deep-sea ***,the irregularity of the conventional molding process,among other reasons,results in low wall thickness uniformity of hollow *** solve this problem,in this work,we developed a biaxial rotation grouting process for deep-sea ceramic hollow buoyancy spheres,which improves the drawbacks of the traditional rotary grouting method that results in poor wall thickness uniformity of the hollow spheres due to its irregular rotational *** this paper,an experimental study was carried out to investigate the effects of different rotational methods,rotational speeds,rotational time,solid phase content,*** the wall thickness uniformity of ceramic hollow *** results show that the hollow floating balls prepared by the biaxial rotation method have the lowest wall thickness standard deviation(0.04)when the rotation speed is 60 rpm,the molding time is 8 min,and the solid phase content is 70 wt%.After the hydrostatic pressure test of 120 MPa,the hydrostatic compressive strength of hollow spheres prepared by the biaxial rotation method was increased by 31.67%compared with that of the traditional process.
Ga-doped Li_(7)La_(3)Zr_(2)O_(12)(Ga-LLZO)has long been considered as a promising garnet-type electrolyte candidate for all-solid-state lithium metal batteries(ASSLBs)due to its high room temperature ionic ***,the typ...
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Ga-doped Li_(7)La_(3)Zr_(2)O_(12)(Ga-LLZO)has long been considered as a promising garnet-type electrolyte candidate for all-solid-state lithium metal batteries(ASSLBs)due to its high room temperature ionic ***,the typical synthesis of Ga-LLZO is usually accompanied by the formation of undesired LiGaO_(2) impurity phase that causes severe instability of the electrolyte in contact with molten Li metal during half/full cell *** this study,we show that by simply engineering the defect chemistry of Ga-LLZO,namely,the lithium deficiency level,LiGaO_(2) impurity phase is effectively inhibited in the final synthetic ***,defect chemistry engineered Ga-LLZO exhibits excellent electrochemical stability against lithium metal,while its high room temperature ionic conductivity(~1.9×10^(-3)S·cm^(-1))is well *** assembled Li/Ga-LLZO/Li symmetric cell has a superior critical current density of 0.9 mA·cm^(-2),and cycles stably for 500 hours at a current density of 0.3 mA·cm^(-2).This research facilitates the potential commercial applications of high performance Ga-LLZO solid electrolytes in ASSLBs.
Most inorganic thermoelectric semiconductors are intrinsically brittle,restricting the application of ther-moelectric ***,developing ductile thermoelectric materials is crucial to thermoelectric technology *** this wo...
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Most inorganic thermoelectric semiconductors are intrinsically brittle,restricting the application of ther-moelectric ***,developing ductile thermoelectric materials is crucial to thermoelectric technology *** this work,single-phase SnTe bulks with dense dislocations were prepared by melting quenching combined with spark plasma *** resulting SnTe thermoelectric materials exhibited a large compressive strain of∼7.5%at room temperature,originating from high-density pre-existing mobile *** initiation of localized slip bands and preferred slip system were also identified by first-principles *** microstructural characterizations reveal that the thermal activated dislocation emission and migration lead to higher compressive strains at intermediate *** 673 K,the deformation mechanism changed from dislocation mediated to grain boundary mediated plasticity,resulting in an ultra-high compressive strain of∼42%.In sum,new insights into the mechanical behavior of SnTe thermoelectric material over a wide range of temperatures were *** work offers the dislocation engineering strategy to design ductile thermoelectric materials for flexi-ble electronics and energy systems.
Industrially prepared artificial graphite(AG)is attractive for potassium-ion batteries(PIBs),but its rate performance is poor and the production process is energy intensive,so developing an efficient strategy to produ...
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Industrially prepared artificial graphite(AG)is attractive for potassium-ion batteries(PIBs),but its rate performance is poor and the production process is energy intensive,so developing an efficient strategy to produce novel graphite with low energy consumption and high performance is economically ***,a nanostructured graphite composed of multi-walled carbon nanotubes(MWCNTs)and graphite shells was prepared by one-pot method through low-temperature pyrolysis of iron-based metal-organic framework(MOF)and carbon *** high graphitization degree of nanostructured graphite makes the initial Coulombic efficiency(ICE)exceed 80%,and the three-dimensional(3D)conductive network ensures a specific capacity of 234 mAh·g^(−1)after 1000 cycles at a high current density of 500 mA·g^(−1).In addition,the typical graphite potassium storage mechanism is also demonstrated by in situ X-ray diffraction(XRD)and in situ Raman spectroscopy,and its practicality is also proved by the voltage of the full *** work provides a feasible way to optimize the practical production process of AG and expand its application in energy storage.
Co/NC catalysts modified with rare earth elements(La,Ce,Pr)were prepared by pyrolysis of rare earth elements doped *** experimental results show that the modification of rare earth elements significantly improves the ...
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Co/NC catalysts modified with rare earth elements(La,Ce,Pr)were prepared by pyrolysis of rare earth elements doped *** experimental results show that the modification of rare earth elements significantly improves the ammonia decomposition activity and stability of the Co/NC *** La-Co/NC catalyst can achieve an 82.3%ammonia decomposition and 18.4 mmol hydrogen production rate at 550℃with a GHSV of 20000 cm^(3)·h^(-1).Furthermore,no obvious performance degradation is observed after 72 hours of reaction for all rare earth elements modified *** is shown that the modification of rare earth elements significantly improves the surface alkalinity and surface chemical state of the catalyst,and thus improves the ammonia decomposition activity of the catalyst.A new type of high-performance ammonia decomposition Co-based catalyst is proposed,and the promoting effect of rare earth elements on the activity of ammonia decomposition is revealed.
The generation and manipulation of spin-polarized electrons at room temperature are essential for the development of advanced spin-optoelectronic *** this work,a one-pot method was used to successfully synthesize homo...
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The generation and manipulation of spin-polarized electrons at room temperature are essential for the development of advanced spin-optoelectronic *** this work,a one-pot method was used to successfully synthesize homogenous Mn:CsPbBr_(3) perovskite quantum dots in air with particle sizes of 7−8 *** effects of Mn doping on the structure,optical and magnetic properties of CsPbBr_(3) quantum dots were *** findings demonstrated proper Mn doping improved the crystallinity and photoluminescence(PL)of quantum *** prepared quantum dots have a narrow full width at half maximum emission(FWHM)of about 17−20 *** magnetic properties of the doped samples and the effect of the magnetic field on the PL spectra properties were *** results show that trace Mn doping can improve the room-temperature ferromagnetism of CsPbBr_(3) quantum *** with magnetic elements makes CsPbBr_(3) quantum dots more responsive to the applied magnetic *** at a lower 50 mT magnetic field,the PL peak of Mn:CsPbBr_(3) still declined 5.91%.Mn:CsPbBr_(3) quantum dots are a new type of multifunctional material that is beneficial to spintronics *** work demonstrates a low-cost synthesis *** should make all-inorganic perovskite quantum dots a promising material for room-temperature spin optoelectronic devices.
Water electrolysis is an important way for high-purity hydrogen production. However, the oxygen evolution reaction(OER), as a key reaction, has a high energy barrier, and the associated catalyst is prone to failure....
Water electrolysis is an important way for high-purity hydrogen production. However, the oxygen evolution reaction(OER), as a key reaction, has a high energy barrier, and the associated catalyst is prone to failure. Therefore, efficient and stable OER catalysts are urgently required. Compared with commercial iridium oxide(IrO2), ruthenium oxide(RuO2) has a lower price and higher catalytic activity for OER due to its location at the near-top of the volcano plot, but has lower structural stability. Thus, an in-depth understanding of the failure mechanism of RuO2is conducive to the reaction pathway design and structural modulation for obtaining higher stable Ru O2catalysts. Here, we discuss recent advances in the enhancement of the stability of RuO2catalysts. First, we analyze in depth the three failure modes of RuO2, including the oxidation of Ru, the lattice oxygen evolution,and the catalyst exfoliation during the OER process. Second, to improve the durability of RuO2catalysts, five modification strategies, comprising defective engineering, strain engineering, phase engineering, interface engineering and microenvironmental engineering, are summarized, and corresponding enhancement mechanisms are also discussed. Finally, the challenges and possible solutions for further breakthroughs of RuO2catalysts are proposed, and the future research trends and prospects of RuO2catalysts are also envisioned. Undoubtedly, this work will contribute to the understanding and design of highly stable OER catalysts and beyond.
The effects of particle size,gradation and solid loading of silicon nitride (Si_(3)N_(4)) on the rheological behavior and curing properties of ceramic slurry are studied by stereolithography (SLA).The results show tha...
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The effects of particle size,gradation and solid loading of silicon nitride (Si_(3)N_(4)) on the rheological behavior and curing properties of ceramic slurry are studied by stereolithography (SLA).The results show that the particle size of Si_(3)N_(4) powder has a signif icant influence on the rheological properties and stability of the *** m_(D50=1.3μm):m_(D50=2.3μm)=3:7,the slurry viscosity is low and the sedimentation is *** most important thing is that with the increase of the solid loading of the slurry,the viscosity of the slurry increases,the stability becomes higher,and the curing thickness *** curing thickness of Si_(3)N_(4) ceramic slurry with solid loading of 50 vol% can reach nearly 50μ*** above results finally show that the process optimizes the formulation of the slurry in rheological and curing properties.
Polyacrylic acid(PAA)hydrogel composites with different hexagonal boron nitride(h-BN)fillers were synthesized and successfully 3D-printed while their thermal conductivity was systematically *** the content of h-BN inc...
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Polyacrylic acid(PAA)hydrogel composites with different hexagonal boron nitride(h-BN)fillers were synthesized and successfully 3D-printed while their thermal conductivity was systematically *** the content of h-BN increasing from 0.1 wt%to 0.3 wt%,the thermal conductivity of the 3D-printed composites has been ***,through the shear force given by the 3D printer,a complete thermal conductivity path is obtained inside the hydrogel,which significantly improves the thermal conductivity of the h-BN hydrogel *** maximum thermal conductivity is 0.8808 W/(m·K),leading to a thermal conductive enhancement of 1000%,compared with the thermal conductivity of pure PAA *** study shows that using h-BN fillers can effectively and significantly improve the thermal conductivity of hydrogelbased materials while its 3D-printable ability has been maintained.
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