Hard carbon(HC) is considered as a commercial candidate for anode materials of sodium-ion batteries due to its low cost and excellent capacity. However, the problem of low initial Coulombic efficiency is still urgentl...Hard carbon(HC) is considered as a commercial candidate for anode materials of sodium-ion batteries due to its low cost and excellent capacity. However, the problem of low initial Coulombic efficiency is still urgently needed to be solved to promote the industrialization of HC.In this paper, 2,2-dimethylvinyl boric acid(DEBA) is used to modify the surface of HC to prepare HC-DEBA materials. During the cycling, the C = C bonds of DEBA molecules will be in situ electro-polymerized to form a polymer network, which can act as the passive protecting layer to inhibit irreversible decomposition of electrolyte,and induce a thinner solid electrolyte interface with lower interface impedance. Therefore, HC-DEBA has higher initial Coulombic efficiency and better cycling stability. In ester-based electrolyte, the initial Coulombic efficiency of the optimized HC-DEBA-3% increases from 65.2% to77.2%. After 2000 cycles at 1 A·g^(-1), the capacity retention rate is 90.92%. Moreover, it can provide a high reversible capacity of 294.7 m Ah·g^(-1) at 50 mA·g^(-1). This simple surface modification method is ingenious and versatile,which can be extended to other energy storage materials.展开更多
In the past two decades,the field of surface-enhanced Raman scattering (SERS) has flourished and many rational strategies have been reported for the successful construction of SERS substrates.However,it still lacks th...In the past two decades,the field of surface-enhanced Raman scattering (SERS) has flourished and many rational strategies have been reported for the successful construction of SERS substrates.However,it still lacks the mass-production and programmability for practical applications with arbitrary configurations,and it is highly desirable to develop SERS substrates with strong signal enhancement,large-scale surface area,easy fabrication and low cost.Herein,we demonstrate a large-area fabrication (1.5 m × 5 m) of low-cost (18.8 dollars per square meter),highly sensitive,flexible and transparent SERS substrate by a simple solution process.The high sensitivity of SERS substrate using 3,3'-diethylthiatricarbocyanine iodide (DTTCI) as probe molecules is strongly dependent on the density and diameter of gold nanoparticles (NPs) on the surface of nylon mesh with the best enhancement factor (EF) of 9.17 × 10^10 and the SERS detection limit of DTTCI molecules is as low as 10-14 M which shows no obvious degradation even after 10,000 cycles of fatigue test,high temperature (above than 160 ℃) and acid-alkali treatment,indicating their excellent stability for the performance in all climates.展开更多
Biological structural materials,despite consisting of limited kinds of compounds,display multifunctionalities due to their complex hierarchical architectures.While some biomimetic strategies have been applied in artif...Biological structural materials,despite consisting of limited kinds of compounds,display multifunctionalities due to their complex hierarchical architectures.While some biomimetic strategies have been applied in artificial materials to enhance their mechanical stability,the simultaneous optimization of other functions along with the mechanical properties via biomimetic designs has not been thoroughly investigated.Herein,iron oxide/carbon nanotube(CNT)-based artificial nacre with both improved mechanical and electromagnetic interference(EMI)shielding performance is fabricated via the mineralization of Fe_(3)O_(4)onto a CNTincorporated matrix.The micro-and nano-structures of the artificial nacre are similar to those of natural nacre,which in turn improves its mechanical properties.The alternating electromagnetic wave-reflective CNT layers and the wave-absorptive iron oxide layers can improve the multiple reflections of the waves on the surfaces of the reflection layers,which then allows sufficient interactions between the waves and the absorption layers.Consequently,compared with the reflection-dependent EMI-shielding of the non-structured material,the artificial nacre exhibits strong absorption-dependent shielding behavior even with a very low content of wave-absorptive phase.Owing to the high mechanical stability,the shielding effectiveness of the artificial nacre that deeply cut by a blade is still maintained at approximately 70%−96%depending on the incident wave frequency.The present work provides a new way for designing structural materials with concurrently enhanced mechanical and functional properties,and a path to combine structural design and intrinsic properties of specific materials via a biomimetic strategy.展开更多
The renowned mechanical performance of biological ceramics can beattributed to their hierarchical structures,wherein structural features atthe nanoscale play a crucial role.However,nanoscale features,such asnanogradie...The renowned mechanical performance of biological ceramics can beattributed to their hierarchical structures,wherein structural features atthe nanoscale play a crucial role.However,nanoscale features,such asnanogradients,have rarely been incorporated in biomimetic ceramicsbecause of the challenges in simultaneously controlling the materialstructure at multiple length scales.Here,we report the fabrication of artificial nacre with graphene oxide nanogradients in its aragonite plateletsthrough a matrix-directed mineralization method.The gradients areformed via the spontaneous accumulation of graphene oxide nanosheetson the surface of the platelets during the mineralization process,whichthen induces a lateral residual stress field in the platelets.Nanoindentation tests and mercury intrusion porosimetry demonstrate that the material's energy dissipation is enhanced both intrinsically and extrinsicallythrough the compressive stress near the platelet surface.The energydissipation density reaches 0.159±0.007 nJ/μm^(3),and the toughnessamplification is superior to that of the most advanced cer amics.Numer-ical simulations also agree with the finding that the stress field not ablycontributes to the overall energy dissipation.This work demonstratesthat the energy dissipation of biomimetic ceramics can be furtherincreased by integrating design principles spanning multiple scales.This strategy can be readily extended to the combinations of other struc-tural models for the design and fabrication of structural ceramics withcustomized and optimized performance.展开更多
基金the National Natural Science Foundation of China(Nos.21975026 and 22005033)Beijing Institute of Technology Research Fund Program for Young Scholars(No.XSQD-202108005)。
文摘Hard carbon(HC) is considered as a commercial candidate for anode materials of sodium-ion batteries due to its low cost and excellent capacity. However, the problem of low initial Coulombic efficiency is still urgently needed to be solved to promote the industrialization of HC.In this paper, 2,2-dimethylvinyl boric acid(DEBA) is used to modify the surface of HC to prepare HC-DEBA materials. During the cycling, the C = C bonds of DEBA molecules will be in situ electro-polymerized to form a polymer network, which can act as the passive protecting layer to inhibit irreversible decomposition of electrolyte,and induce a thinner solid electrolyte interface with lower interface impedance. Therefore, HC-DEBA has higher initial Coulombic efficiency and better cycling stability. In ester-based electrolyte, the initial Coulombic efficiency of the optimized HC-DEBA-3% increases from 65.2% to77.2%. After 2000 cycles at 1 A·g^(-1), the capacity retention rate is 90.92%. Moreover, it can provide a high reversible capacity of 294.7 m Ah·g^(-1) at 50 mA·g^(-1). This simple surface modification method is ingenious and versatile,which can be extended to other energy storage materials.
基金the National Natural Science Foundation of China (Nos.51732011,21431006,2176113200& 21401183 and 21771168)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China (No.21521001)+5 种基金Key Research Program of Frontier Sciences,CAS (No.QYZDJ-SSWSLH036)the National Basic Research Program of China (No.2014CB931800)the Users with Excellence and Scientific Research Grant of Hefei Science Center of CAS (No.2015HSC-UE007)the Fundamental Research Funds for the Central Universities (Nos.WK2100000005 and WK2090050043)the Joint Funds from Hefei National Synchrotron Radiation Laboratory (No.UN2018LHJJ)This work was partially carried out at the USTC Center for Micro and Nanoscale Research and Fabrication.
文摘In the past two decades,the field of surface-enhanced Raman scattering (SERS) has flourished and many rational strategies have been reported for the successful construction of SERS substrates.However,it still lacks the mass-production and programmability for practical applications with arbitrary configurations,and it is highly desirable to develop SERS substrates with strong signal enhancement,large-scale surface area,easy fabrication and low cost.Herein,we demonstrate a large-area fabrication (1.5 m × 5 m) of low-cost (18.8 dollars per square meter),highly sensitive,flexible and transparent SERS substrate by a simple solution process.The high sensitivity of SERS substrate using 3,3'-diethylthiatricarbocyanine iodide (DTTCI) as probe molecules is strongly dependent on the density and diameter of gold nanoparticles (NPs) on the surface of nylon mesh with the best enhancement factor (EF) of 9.17 × 10^10 and the SERS detection limit of DTTCI molecules is as low as 10-14 M which shows no obvious degradation even after 10,000 cycles of fatigue test,high temperature (above than 160 ℃) and acid-alkali treatment,indicating their excellent stability for the performance in all climates.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Nos.XDB 0470303 and XDB 0450402)the National Key Research and Development Program of China(Nos.2018YFE0202201 and 2021YFA0715700)+2 种基金the National Natural Science Foundation of China(Nos.22293044,U1932213,and 22305240)the New Cornerstone Investigator Program.Y.-F.M.acknowledges the Major Basic Research Project of Anhui Province(No.2023z04020009)the Double First-Class University Construction Fund from USTC(No.YD2060002037).
文摘Biological structural materials,despite consisting of limited kinds of compounds,display multifunctionalities due to their complex hierarchical architectures.While some biomimetic strategies have been applied in artificial materials to enhance their mechanical stability,the simultaneous optimization of other functions along with the mechanical properties via biomimetic designs has not been thoroughly investigated.Herein,iron oxide/carbon nanotube(CNT)-based artificial nacre with both improved mechanical and electromagnetic interference(EMI)shielding performance is fabricated via the mineralization of Fe_(3)O_(4)onto a CNTincorporated matrix.The micro-and nano-structures of the artificial nacre are similar to those of natural nacre,which in turn improves its mechanical properties.The alternating electromagnetic wave-reflective CNT layers and the wave-absorptive iron oxide layers can improve the multiple reflections of the waves on the surfaces of the reflection layers,which then allows sufficient interactions between the waves and the absorption layers.Consequently,compared with the reflection-dependent EMI-shielding of the non-structured material,the artificial nacre exhibits strong absorption-dependent shielding behavior even with a very low content of wave-absorptive phase.Owing to the high mechanical stability,the shielding effectiveness of the artificial nacre that deeply cut by a blade is still maintained at approximately 70%−96%depending on the incident wave frequency.The present work provides a new way for designing structural materials with concurrently enhanced mechanical and functional properties,and a path to combine structural design and intrinsic properties of specific materials via a biomimetic strategy.
基金Strategic Priority Research Program of the Chinese Acad-emy of Sciences(XDB 0470000)National Key Research and Development Program of China(2018YFE0202201 and 2021YFA0715700)+4 种基金National Natural Science Foundation of China(22305240 and 22293044)Y.F.M.acknowledges the funding suported by the Students'Innovation and Entrepreneurship Foundation of USTC(XY2022S02)Double First-Class University Construction Fund from USTC(YD2060002037)New Comerstone Science FoundationThis work was parially carried out at the USTC Center for Micro-and Nanoscale Research and Fabrication.This research used Beamline BL14B and BL15U of the Shanghai Synchrotron Radiation Fa cility(SSRF).
文摘The renowned mechanical performance of biological ceramics can beattributed to their hierarchical structures,wherein structural features atthe nanoscale play a crucial role.However,nanoscale features,such asnanogradients,have rarely been incorporated in biomimetic ceramicsbecause of the challenges in simultaneously controlling the materialstructure at multiple length scales.Here,we report the fabrication of artificial nacre with graphene oxide nanogradients in its aragonite plateletsthrough a matrix-directed mineralization method.The gradients areformed via the spontaneous accumulation of graphene oxide nanosheetson the surface of the platelets during the mineralization process,whichthen induces a lateral residual stress field in the platelets.Nanoindentation tests and mercury intrusion porosimetry demonstrate that the material's energy dissipation is enhanced both intrinsically and extrinsicallythrough the compressive stress near the platelet surface.The energydissipation density reaches 0.159±0.007 nJ/μm^(3),and the toughnessamplification is superior to that of the most advanced cer amics.Numer-ical simulations also agree with the finding that the stress field not ablycontributes to the overall energy dissipation.This work demonstratesthat the energy dissipation of biomimetic ceramics can be furtherincreased by integrating design principles spanning multiple scales.This strategy can be readily extended to the combinations of other struc-tural models for the design and fabrication of structural ceramics withcustomized and optimized performance.
