Micrometer-sized MoO2 hollow spheres were synthesized hydrothermally with ammonium heptamolybdate tetrahydrate as molybdenum source, Cetyltrimethylammonium bromide as structure-directing agent and C2H5OH as reducing a...Micrometer-sized MoO2 hollow spheres were synthesized hydrothermally with ammonium heptamolybdate tetrahydrate as molybdenum source, Cetyltrimethylammonium bromide as structure-directing agent and C2H5OH as reducing agent, respectively. The products were investigated by X-ray diffraction, thermo gravimetry and differential thermal analysis, scanning electron microscopy, transmission electron micraseopy and X-ray photoelectron spectroscopy. A morphology transition of ＂blocks-solid spheres-hollow spheres＂ during the growth procfess was observed and the possible mechanism for the formation of MoO2 samples was proposed to be through a microscale Kirkendall effcct.展开更多
Various nanostructured architectures have been demonstrated to be effective to address the issues of high capacity Si anodes. However, the scale-up of these nano-Si materials is still a critical obstacle for commercia...Various nanostructured architectures have been demonstrated to be effective to address the issues of high capacity Si anodes. However, the scale-up of these nano-Si materials is still a critical obstacle for commercialization. Herein, we use industrial ferrosilicon as low-cost Si source and introduce a facile and scalable method to fabricate a micrometer-sized ferrosilicon/C composite anode, in which ferrosilicon microparticles are wrapped with multi-layered carbon nanosheets. The multi-layered carbon nanosheets could effectively buffer the volume variation of Si as well as create an abundant and reliable conductivity framework, ensuring fast transport of electrons. As a result, the micrometer-sized ferrosilicon/C anode achieves a stable cycling with 805.9 m Ah g-1 over 200 cycles at 500 mA g-1 and a good rate capability of455.6 mAh g-1 at 10 A g-1. Therefore, our approach based on ferrosilicon provides a new opportunity in fabricating cost-effective, pollution-free, and large-scale Si electrode materials for high energy lithium-ion batteries.展开更多
Graphene oxide(GO)is widely used in the construction and application of various 2 D membrane-based materials due to its unique colloidal structure.Herein,we demonstrate that micrometer-sized particles can make up free...Graphene oxide(GO)is widely used in the construction and application of various 2 D membrane-based materials due to its unique colloidal structure.Herein,we demonstrate that micrometer-sized particles can make up freestanding membranes enabled by the extraordinary amphiphilic and polymer-like properties of graphene oxide through freeze casting.The 2 D macromolecule,GO could well wrap the particles for better uniformity and stability in either dispersion or membrane.Importantly,freeze casting plays an important role in avoiding the severe aggregation of micrometer-sized particles in the solventremoving process.After reduction,the membrane exhibits good electrical conductivity while maintaining its integral structure,which can be directly used as a freestanding binder-free electrode.This work provides a universal approach to fabricate freestanding membranes with various micrometersized materials for energy storage.展开更多
B4C/6061Al composites reinforced with nano-to micrometer-sized B4C particles were fabricated via powder metallurgy route consisting of spark plasma sintering(SPS)and hot extrusion and rolling(HER),followed by T6 treat...B4C/6061Al composites reinforced with nano-to micrometer-sized B4C particles were fabricated via powder metallurgy route consisting of spark plasma sintering(SPS)and hot extrusion and rolling(HER),followed by T6 treatment.The microstructural evolution and mechanical properties were investigated.Results showed that the status of B4C particles changed from a network after SPS to a dispersion distribution after HER.The substructured grains reached 66.5%owing to the pinning effect of nano-sized B4C,and the grain size was refined from 3.12μm to 1.56μm after HER.After T6 treatment,dispersed Mg_(2)Si precipitated phases formed,and the grain size increased to 1.87μm.Fine recrystallized grains around micro-sized B4C were smaller than those in the areas with uniform distribution of nano-sized B4C and Mg_(2)Si.The stress distributions of as-rolled and heated composites were similar,considering that the T6 heat treatment was only effective in eliminating the first internal stress.The Vickers,microhardness,and tensile strength of as-SPSed composites were greatly improved from HV 55.45,0.86 GPa,and 180 MPa to HV 77.51,1.08 GPa,and 310 MPa,respectively.Despite the precipitation strengthening,the corresponding values of as-heated composites decreased to HV 70.82,0.85 GPa,and 230 MPa owing to grain coarsening.展开更多
The fundamental research and potential applications of magnetic two-dimensional(2D)ternary chalcogenides in spintronics have garnered considerable interest.Lessening the thickness of non-van der Waals(nvdWs)ternary ch...The fundamental research and potential applications of magnetic two-dimensional(2D)ternary chalcogenides in spintronics have garnered considerable interest.Lessening the thickness of non-van der Waals(nvdWs)ternary chalcogenides to 2D structures can bring about novel physical phenomena and contribute to their potential applications m spintronics.In this paper,a template-mediated chemical synthesis was proposed to prepare nvdWs2D micrometer-sized CuFeSeS composite nanosheets.Specifically,free-standing 2D nvdWs hexagonal CuFeSeS with a mean size of 2.6μm was successfully achieved.The anisotropic growth of CuFeSeS was induced by the confinement effect of the template.Inspiringly,the 2D hexagonal CuFeSeS nanosheets with higher Fe content exhibit intrinsic ferromagnetic order,with a huge coercivity(HC)of 10.99 kOe at 5 K.The magnetism is regulated by varying the Fe content and reaction temperature.The valence changes of Fe,which form the ferromagnetic Fe7S8phase,play a crucial role in the magnetic transitions.This work enlightens the synthesis of 2D nvdWs ternary chalcogenides and promotes the potential applications of2D hexagonal CuFeSeS nanosheets in spintronics.展开更多
Micrometer-sized silicon oxide(SiO)anodes encounter challenges in large-scale applications due to significant volume expansion during the alloy/de-alloy process.Herein,an innovative deep eutectic electrolyte derived f...Micrometer-sized silicon oxide(SiO)anodes encounter challenges in large-scale applications due to significant volume expansion during the alloy/de-alloy process.Herein,an innovative deep eutectic electrolyte derived from succinonitrile is introduced to enhance the cycling stability of SiO anodes.Density functional theory calculations validate a robust ion-dipole interaction between lithium ions(Li^(+))and succinonitrile(SN).The cosolvent fluoroethylene carbonate(FEC)optimizes the Li^(+)solvation structure in the SN-based electrolyte with its weakly solvating ability.Molecular dynamics simulations investigate the regulating mechanism of ion-dipole and cation-anion interaction.The unique Li^(+)solvation structure,enriched with FEC and TFSI^(-),facilitates the formation of an inorganic-organic composite solid electrolyte interphase on SiO anodes.Micro-CT further detects the inhibiting effect on the SiO volume expansion.As a result,the SiO|LiCoO_(2) full cells exhibit excellent electrochemical performance in deep eutectic-based electrolytes.This work presents an effective strategy for extending the cycle life of SiO anodes by designing a new SN-based deep eutectic electrolyte.展开更多
文摘Micrometer-sized MoO2 hollow spheres were synthesized hydrothermally with ammonium heptamolybdate tetrahydrate as molybdenum source, Cetyltrimethylammonium bromide as structure-directing agent and C2H5OH as reducing agent, respectively. The products were investigated by X-ray diffraction, thermo gravimetry and differential thermal analysis, scanning electron microscopy, transmission electron micraseopy and X-ray photoelectron spectroscopy. A morphology transition of ＂blocks-solid spheres-hollow spheres＂ during the growth procfess was observed and the possible mechanism for the formation of MoO2 samples was proposed to be through a microscale Kirkendall effcct.
基金the National Natural Science Foundation of China(No:21703285)。
文摘Various nanostructured architectures have been demonstrated to be effective to address the issues of high capacity Si anodes. However, the scale-up of these nano-Si materials is still a critical obstacle for commercialization. Herein, we use industrial ferrosilicon as low-cost Si source and introduce a facile and scalable method to fabricate a micrometer-sized ferrosilicon/C composite anode, in which ferrosilicon microparticles are wrapped with multi-layered carbon nanosheets. The multi-layered carbon nanosheets could effectively buffer the volume variation of Si as well as create an abundant and reliable conductivity framework, ensuring fast transport of electrons. As a result, the micrometer-sized ferrosilicon/C anode achieves a stable cycling with 805.9 m Ah g-1 over 200 cycles at 500 mA g-1 and a good rate capability of455.6 mAh g-1 at 10 A g-1. Therefore, our approach based on ferrosilicon provides a new opportunity in fabricating cost-effective, pollution-free, and large-scale Si electrode materials for high energy lithium-ion batteries.
文摘Graphene oxide(GO)is widely used in the construction and application of various 2 D membrane-based materials due to its unique colloidal structure.Herein,we demonstrate that micrometer-sized particles can make up freestanding membranes enabled by the extraordinary amphiphilic and polymer-like properties of graphene oxide through freeze casting.The 2 D macromolecule,GO could well wrap the particles for better uniformity and stability in either dispersion or membrane.Importantly,freeze casting plays an important role in avoiding the severe aggregation of micrometer-sized particles in the solventremoving process.After reduction,the membrane exhibits good electrical conductivity while maintaining its integral structure,which can be directly used as a freestanding binder-free electrode.This work provides a universal approach to fabricate freestanding membranes with various micrometersized materials for energy storage.
基金Projects(51775366,51805358)supported by the National Natural Science Foundation of ChinaProject(20130321024)supported by the Key Science and Technology Program of Shanxi Province,China。
文摘B4C/6061Al composites reinforced with nano-to micrometer-sized B4C particles were fabricated via powder metallurgy route consisting of spark plasma sintering(SPS)and hot extrusion and rolling(HER),followed by T6 treatment.The microstructural evolution and mechanical properties were investigated.Results showed that the status of B4C particles changed from a network after SPS to a dispersion distribution after HER.The substructured grains reached 66.5%owing to the pinning effect of nano-sized B4C,and the grain size was refined from 3.12μm to 1.56μm after HER.After T6 treatment,dispersed Mg_(2)Si precipitated phases formed,and the grain size increased to 1.87μm.Fine recrystallized grains around micro-sized B4C were smaller than those in the areas with uniform distribution of nano-sized B4C and Mg_(2)Si.The stress distributions of as-rolled and heated composites were similar,considering that the T6 heat treatment was only effective in eliminating the first internal stress.The Vickers,microhardness,and tensile strength of as-SPSed composites were greatly improved from HV 55.45,0.86 GPa,and 180 MPa to HV 77.51,1.08 GPa,and 310 MPa,respectively.Despite the precipitation strengthening,the corresponding values of as-heated composites decreased to HV 70.82,0.85 GPa,and 230 MPa owing to grain coarsening.
基金financially supported by the National Natural Science Foundation of China(No.52202340)the Applied Basic Research Project of Shanxi Province(No.20210302124425)+2 种基金the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(No.2021L266)the Graduate Research and Innovation Project of Shanxi Province(No.2024KY472)the Graduate Science and Technology Innovation Project Foundation of Shanxi Normal University(No.2023XSY065)
文摘The fundamental research and potential applications of magnetic two-dimensional(2D)ternary chalcogenides in spintronics have garnered considerable interest.Lessening the thickness of non-van der Waals(nvdWs)ternary chalcogenides to 2D structures can bring about novel physical phenomena and contribute to their potential applications m spintronics.In this paper,a template-mediated chemical synthesis was proposed to prepare nvdWs2D micrometer-sized CuFeSeS composite nanosheets.Specifically,free-standing 2D nvdWs hexagonal CuFeSeS with a mean size of 2.6μm was successfully achieved.The anisotropic growth of CuFeSeS was induced by the confinement effect of the template.Inspiringly,the 2D hexagonal CuFeSeS nanosheets with higher Fe content exhibit intrinsic ferromagnetic order,with a huge coercivity(HC)of 10.99 kOe at 5 K.The magnetism is regulated by varying the Fe content and reaction temperature.The valence changes of Fe,which form the ferromagnetic Fe7S8phase,play a crucial role in the magnetic transitions.This work enlightens the synthesis of 2D nvdWs ternary chalcogenides and promotes the potential applications of2D hexagonal CuFeSeS nanosheets in spintronics.
基金supported by the National Natural Science Foundation of China(22279026)the National Key Research and Development Program of China(2022YFE0138900)+2 种基金the Young Elite Scientist sponsorship program by CAST(no.20200148)the Natural Science Funds of Heilongjiang Province(YQ2021B003)the Fundamental Research Funds for the Central Universities(grant no.HIT.OCEF.2022017).
文摘Micrometer-sized silicon oxide(SiO)anodes encounter challenges in large-scale applications due to significant volume expansion during the alloy/de-alloy process.Herein,an innovative deep eutectic electrolyte derived from succinonitrile is introduced to enhance the cycling stability of SiO anodes.Density functional theory calculations validate a robust ion-dipole interaction between lithium ions(Li^(+))and succinonitrile(SN).The cosolvent fluoroethylene carbonate(FEC)optimizes the Li^(+)solvation structure in the SN-based electrolyte with its weakly solvating ability.Molecular dynamics simulations investigate the regulating mechanism of ion-dipole and cation-anion interaction.The unique Li^(+)solvation structure,enriched with FEC and TFSI^(-),facilitates the formation of an inorganic-organic composite solid electrolyte interphase on SiO anodes.Micro-CT further detects the inhibiting effect on the SiO volume expansion.As a result,the SiO|LiCoO_(2) full cells exhibit excellent electrochemical performance in deep eutectic-based electrolytes.This work presents an effective strategy for extending the cycle life of SiO anodes by designing a new SN-based deep eutectic electrolyte.
