Silicon is considered as one of the most promising anodes for Li-ion batteries(LIBs), but it is limited for commercial applications by the critical issue of large volume expansion during the lithiation. In this work, ...Silicon is considered as one of the most promising anodes for Li-ion batteries(LIBs), but it is limited for commercial applications by the critical issue of large volume expansion during the lithiation. In this work, the structure of silicon/carbon(Si/C) particles on graphene sheets(Si/C–G) was obtained to solve the issue by using the void space of Si/C particles and graphene. Si/C–G material was from Si/PDA-GO that silicon particles was coated by polydopamine(PDA) and reacted with oxide graphene(GO). The Si/C–G material have good cycling performance as the stability of the structure during the lithiation/dislithiation.The Si/C–G anode materials exhibited high reversible capacity of 1910.5 mA h g^(-1) and 1196.1 mA h g^(-1) after 700 cycles at 357.9 m A g^(-1), and have good rate property of 507.2 mA h g^(-1) at high current density,showing significantly improved commercial viability of silicon electrodes in high-energy-density LIBs.展开更多
The hypoeutectic composite material composed of BCC phase and in situ precipitated Ti_(5)Si_(3) was prepared by adding Si into MoNbTaTiV high-entropy alloy.The obvious oriented in situ Ti_(5)Si_(3) phase formed eutect...The hypoeutectic composite material composed of BCC phase and in situ precipitated Ti_(5)Si_(3) was prepared by adding Si into MoNbTaTiV high-entropy alloy.The obvious oriented in situ Ti_(5)Si_(3) phase formed eutectic phase with BCC phase in the inter-dendritic area,which leads to excellent properties of the composite.The alloy exhibits ultra-high yield stress of 718 MPa at 1200℃ and obvious compression plasticity.After reaching the maximum strength,dynamic recovery(DRV)and dynamic recrystallization(DRX)caused soften phenomena.The DRX mechanism of the dual-phase eutectic structure is analyzed by electron backscatter diffraction.The DRX of the BCC phase conforms to the discontinuous DRX and continuous DRX mechanisms,while the Ti_(5)Si_(3) phase has a geometric DRX mechanism in addition to the above two mechanisms.The high performance of this composite has enough potential high-temperature applications such as nuclear and aero engine.展开更多
To overcome the trade-off between the devisable micro structure and the excellent tensile ductility of bulk metallic glass composites(BMGCs),a novel ex-situ and in-situ hybrid strategy is successfully proposed to desi...To overcome the trade-off between the devisable micro structure and the excellent tensile ductility of bulk metallic glass composites(BMGCs),a novel ex-situ and in-situ hybrid strategy is successfully proposed to design a series of the work-hardenable ductile Ti-based multilayered BMGCs(ML-BMGCs).The asprepared ML-BMGCs,consisting of α-phases,β-phases and amorphous phases,exhibit a controllable multilayered structure of the Ti layers and the amorphous layers with alternative distribution.The size and volume fraction of the crystalline phases are tuned by Nb microalloying.It is found that the ML-BMGCs possess a suitable size and volume fraction of the crystalline phases when Nb microalloying content are5%(at.) or 8%(at.),and they obtain an optimum combination of the specific strength of 243 MPa g kg-1 or 216 MPa g kg-1,and tensile plasticity of 4.33%±0.1 % or 5.10%±0.1%.The deformation mechanism of the as-prepared ML-BMGCs during tension is also revealed.The ex-situ Ti layers and in-situ dendrites together effectively serve as absorbers to suppress the propagation of shear bands and multiply shear bands.And the defo rmation of ex-situ α-Ti phases by dislocation slip and the transformation from in-situ metastable β-Ti phase to orthorhombic α-Ti during tension impart significant work-hardening capability to the ML-B MGCs.The present study provides a guidance of developing novel high-performance BMGCs with a controllable micro structure.展开更多
The functional copper nanocomposites(Cu NCs)have received increasing attention in the environmental catalysis application for wastewater treatment due to their superior catalytic activity and reactivity.However,overco...The functional copper nanocomposites(Cu NCs)have received increasing attention in the environmental catalysis application for wastewater treatment due to their superior catalytic activity and reactivity.However,overcoming the pH limitations towards the neutral and alkaline wastewater remains a tricky challenge.In this work,we demonstrate a green strategy to synthesize Cu NCs with coexistence of active Cu,Cu_(2)O and ZrO_(2)by self-propagating combustion of metallic glassy ribbons,which exhibit the extremely superior catalytic performance for degradation reaction,providing full conversion of organic dyes completely to the environmental friendly small species(efficiency>99%)under acidic,neutral and alkaline conditions.Compared with all other catalysts developed thus far,the novel Cu NCs catalysts with more active sites present much enhanced catalytic capability of degradation efficiency without the use of any chemical reagents for neutral and alkaline organic dye solutions.The possible decomposition pathways of organic dyes for different p H systems were systematically investigated.More importantly,the two kinds of catalytic mechanism related to high reactivity of nanoscale Cu/Cu_(2)O and strong oxidizing capability of activated·OH/·O_(2)^(-)radicals can also be successfully confirmed under different pH conditions.The green synthetic approach can be extended to design the various M-based nanocomposites(M=Fe,Co,Ni,Ag,Pd)as efficient catalysts for the functional applications of many chemical reactions.展开更多
基金financial support from National Natural Science Foundation of China(Nos.51525206,51927803,51902316)National Key R&D Program of China(2016YFA0200102 and 2016YFB0100100)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA22010602)Liaoning Revitalization Talents Program(No.XLYC1908015)。
文摘Silicon is considered as one of the most promising anodes for Li-ion batteries(LIBs), but it is limited for commercial applications by the critical issue of large volume expansion during the lithiation. In this work, the structure of silicon/carbon(Si/C) particles on graphene sheets(Si/C–G) was obtained to solve the issue by using the void space of Si/C particles and graphene. Si/C–G material was from Si/PDA-GO that silicon particles was coated by polydopamine(PDA) and reacted with oxide graphene(GO). The Si/C–G material have good cycling performance as the stability of the structure during the lithiation/dislithiation.The Si/C–G anode materials exhibited high reversible capacity of 1910.5 mA h g^(-1) and 1196.1 mA h g^(-1) after 700 cycles at 357.9 m A g^(-1), and have good rate property of 507.2 mA h g^(-1) at high current density,showing significantly improved commercial viability of silicon electrodes in high-energy-density LIBs.
基金financially supported by the National Key Research and Development Program(No.2018YFB0703402)the National Natural Science Foundation of China(Nos.51790484,52074257)+2 种基金the Chinese Academy of Sciences(No.ZDBS-LY-JSC023)the Dongguan Innovative Research Team Program(No.2014607134)the Science and Technology on Transient Impact Laboratory(No.6142606192208).
文摘The hypoeutectic composite material composed of BCC phase and in situ precipitated Ti_(5)Si_(3) was prepared by adding Si into MoNbTaTiV high-entropy alloy.The obvious oriented in situ Ti_(5)Si_(3) phase formed eutectic phase with BCC phase in the inter-dendritic area,which leads to excellent properties of the composite.The alloy exhibits ultra-high yield stress of 718 MPa at 1200℃ and obvious compression plasticity.After reaching the maximum strength,dynamic recovery(DRV)and dynamic recrystallization(DRX)caused soften phenomena.The DRX mechanism of the dual-phase eutectic structure is analyzed by electron backscatter diffraction.The DRX of the BCC phase conforms to the discontinuous DRX and continuous DRX mechanisms,while the Ti_(5)Si_(3) phase has a geometric DRX mechanism in addition to the above two mechanisms.The high performance of this composite has enough potential high-temperature applications such as nuclear and aero engine.
基金supported financially by the National Nature Science Foundation of China (Nos. 51790484 and 51531005)National Key Research and Development Program (No. 2018YFB0703402)+1 种基金Liao Ning Revitalization program (Nos. XLYC1802078 and XLYC1807062)Shenyang Amorphous Metal Manufacturing Co., Ltd。
文摘To overcome the trade-off between the devisable micro structure and the excellent tensile ductility of bulk metallic glass composites(BMGCs),a novel ex-situ and in-situ hybrid strategy is successfully proposed to design a series of the work-hardenable ductile Ti-based multilayered BMGCs(ML-BMGCs).The asprepared ML-BMGCs,consisting of α-phases,β-phases and amorphous phases,exhibit a controllable multilayered structure of the Ti layers and the amorphous layers with alternative distribution.The size and volume fraction of the crystalline phases are tuned by Nb microalloying.It is found that the ML-BMGCs possess a suitable size and volume fraction of the crystalline phases when Nb microalloying content are5%(at.) or 8%(at.),and they obtain an optimum combination of the specific strength of 243 MPa g kg-1 or 216 MPa g kg-1,and tensile plasticity of 4.33%±0.1 % or 5.10%±0.1%.The deformation mechanism of the as-prepared ML-BMGCs during tension is also revealed.The ex-situ Ti layers and in-situ dendrites together effectively serve as absorbers to suppress the propagation of shear bands and multiply shear bands.And the defo rmation of ex-situ α-Ti phases by dislocation slip and the transformation from in-situ metastable β-Ti phase to orthorhombic α-Ti during tension impart significant work-hardening capability to the ML-B MGCs.The present study provides a guidance of developing novel high-performance BMGCs with a controllable micro structure.
基金Financial supports from the National Natural Science Foundation of China(51801209,51790484)Liaoning Revitalization Talents Program(XLYC1802078 and XLYC1807062)the fund of Qingdao(19-9-2-1-wz)。
文摘The functional copper nanocomposites(Cu NCs)have received increasing attention in the environmental catalysis application for wastewater treatment due to their superior catalytic activity and reactivity.However,overcoming the pH limitations towards the neutral and alkaline wastewater remains a tricky challenge.In this work,we demonstrate a green strategy to synthesize Cu NCs with coexistence of active Cu,Cu_(2)O and ZrO_(2)by self-propagating combustion of metallic glassy ribbons,which exhibit the extremely superior catalytic performance for degradation reaction,providing full conversion of organic dyes completely to the environmental friendly small species(efficiency>99%)under acidic,neutral and alkaline conditions.Compared with all other catalysts developed thus far,the novel Cu NCs catalysts with more active sites present much enhanced catalytic capability of degradation efficiency without the use of any chemical reagents for neutral and alkaline organic dye solutions.The possible decomposition pathways of organic dyes for different p H systems were systematically investigated.More importantly,the two kinds of catalytic mechanism related to high reactivity of nanoscale Cu/Cu_(2)O and strong oxidizing capability of activated·OH/·O_(2)^(-)radicals can also be successfully confirmed under different pH conditions.The green synthetic approach can be extended to design the various M-based nanocomposites(M=Fe,Co,Ni,Ag,Pd)as efficient catalysts for the functional applications of many chemical reactions.
