Lightweight,flexibility,and low thickness are urgent requirements for next-generation high-performance electromagnetic interference(EMI)shielding materials for catering to the demand for smart and wearable electronic ...Lightweight,flexibility,and low thickness are urgent requirements for next-generation high-performance electromagnetic interference(EMI)shielding materials for catering to the demand for smart and wearable electronic devices.Although several efforts have focused on constructing porous and flexible conductive films or aerogels,few studies have achieved a balance in terms of density,thickness,flexibility,and EMI shielding effectiveness(SE).Herein,an ultrathin,lightweight,and flexible carbon nanotube(CNT)buckypaper enhanced using MXenes(Ti3C2Tx)for high-performance EMI shielding is synthesized through a facile electrophoretic deposition process.The obtained Ti3C2Tx@CNT hybrid buckypaper exhibits an outstanding EMI SE of 60.5 dB in the X-band at 100μm.The hybrid buckypaper with an MXene content of 49.4 wt%exhibits an EMI SE of 50.4 dB in the X-band with a thickness of only 15μm,which is 105%higher than that of pristine CNT buckypaper.Furthermore,an average specific SE value of 5.7×10^(4) dB cm^(2) g^(−1) is exhibited in the 5-μm hybrid buckypaper.Thus,this assembly process proves promising for the construction of ultrathin,flexible,and high-performance EMI shielding films for application in electronic devices and wireless communications.展开更多
High-purity(99%)carbon nanocoils(CNCs)have been synthesized by using porousα-Fe2O3/SnO2 catalyst.The yield of CNCs reaches 9,098%after a 6 h growth.This value is much higher than the previously reported data,indicati...High-purity(99%)carbon nanocoils(CNCs)have been synthesized by using porousα-Fe2O3/SnO2 catalyst.The yield of CNCs reaches 9,098%after a 6 h growth.This value is much higher than the previously reported data,indicating that this method is promising to synthesize high-purity CNCs on a large scale.It is considered that an appropriate proportion of Fe and Sn,proper particle size distribution,and a loose-porous aggregate structure of the catalyst are the key points to the high-purity growth of CNCs.Benefiting from the high-purity preparation,a CNC Buckypaper was successfully prepared and the electrical,mechanical,and electrochemical properties were investigated comprehensively.Furthermore,as one of the practical applications,the CNC Buckypaper was successfully utilized as an efficient adsorbent for the removal of methylene blue dye from wastewater with an adsorption efficiency of 90.9%.This study provides a facile and economical route for preparing high-purity CNCs,which is suitable for large-quantity production.Furthermore,the fabrication of macroscopic CNC Buckypaper provides promising alternative of adsorbent or other practical applications.展开更多
Lithium-sulfur batteries(LSBs)are considered as the next generation of advanced rechargeable batteries because of their high energy density.In this study,sulfur and CoxS electrocatalyst are deposited on carbon nanotub...Lithium-sulfur batteries(LSBs)are considered as the next generation of advanced rechargeable batteries because of their high energy density.In this study,sulfur and CoxS electrocatalyst are deposited on carbon nanotube buckypaper(S/CoxS/BP)by a facile electrodeposition method and are used as a binder-free high-performance cathode for LSBs.Elemental sulfur is deposited on buckypaper by electrooxidation of a polysulfide solution(-S6^2-).This approach substantially increased the current and time efficiency of sulfur electrochemical deposition on conductive material for LSBs.S/CoxS/BP cathode could deliver an initial discharge capacity as high as 1650 mAh g^-1 at 0.1 C,which is close to the theoretical capacity of sulfur.At current rate of 0.5 C,the S/CoxS/BP has a capacity of 1420 mAh g^-1 at the first cycle and 715 mAh g^-1 after 500 cycles with a fading rate of 0.099%per cycle.The high capacity of S/CoxS/BP is attributed to both the homogeneous dispersion of nanosized sulfur within BP and the presence of CoxS catalyst.The sodium dodecyl sulfate(SDS)pretreatment of BP renders it polarity to bind polysulfides and thus facilitates the good dispersibility of nanosized sulfur within BP.CoxS catalyst accelerates the kinetics of polysulfide conversion and reduces the presence of polysulfide in the cathode,which suppresses the polysulfide diffusion to anode,i.e.,the shuttle effect.The mitigation of the active material loss improves not only the capacity but also the cyclability of S/CoxS/BP.展开更多
The electrical conductivity of carbon nanotube buckypapers can be dramatically increased by incorporation of silver particles contained in a commercial silver paste.Two methods,co-dispersion during the production of b...The electrical conductivity of carbon nanotube buckypapers can be dramatically increased by incorporation of silver particles contained in a commercial silver paste.Two methods,co-dispersion during the production of buckypaper and surface coating on a preformed buckypaper,were used to prepare composite buckypapers.The two types of composite buckypapers exhibited very different electrical conductivity profiles.The composite buckypapers prepared by the surface coating method showed a distinct step transition in electrical conductivity at 3 vol%silver content,leading to a 15-fold improvement at 6%silver content.The composite buckypapers prepared by the co-dispersion method showed a gradual change in electrical conductivity with increasing silver particle content,resulting in a five-fold improvement at12%silver content.Surface and sectional morphologies of the two types of composite buckypapers were examined and related to their electrical conductivity profiles.展开更多
Fiber-reinforced resin-based plastics are widely used in structural composites for aerospace and automotive applications,and they often face extreme load conditions in actual working environments.It is challenging to ...Fiber-reinforced resin-based plastics are widely used in structural composites for aerospace and automotive applications,and they often face extreme load conditions in actual working environments.It is challenging to monitor the damage of the structure during the vibration process.This study was aimed at using buckypaper(BP)sensors to monitor the structural health status of composite structures under ambient vibrations.First,the feasibility of flexible printed circuit instead of wire is verified by the tensile experiment.Then the vibration monitoring experiment of the composite cantilever beam is carried out by using BP sensors systematically.The sweep frequency experiment determines the excitation frequency of the cantilever beam.Low-period vibration fatigue cycle and high-period vibration fatigue cycle experiments are designed to verify the vibration monitoring method using BP sensors.Besides,the signal response of BP sensors in the vibration experiment is analyzed,and the relationship betweenΔR/R0 and vibration acceleration is obtained.Finally,through the change law ofΔR/R0 of the sensor,the cumulative damage caused by vibration fatigue is visualized.It is demonstrated that the monitoring method based on BP sensors can be applied to study the damage behavior of composite structure under the vibration environment.展开更多
基金National Natural Science Foundation of China(Grant Nos.52072415,52072306 and 51772335)the Science and Technology Program of Guangzhou(201904010450)Science Foundation of the National Key Laboratory of Science and Technology on Advanced Composites in Special Environments(6142905192509).
文摘Lightweight,flexibility,and low thickness are urgent requirements for next-generation high-performance electromagnetic interference(EMI)shielding materials for catering to the demand for smart and wearable electronic devices.Although several efforts have focused on constructing porous and flexible conductive films or aerogels,few studies have achieved a balance in terms of density,thickness,flexibility,and EMI shielding effectiveness(SE).Herein,an ultrathin,lightweight,and flexible carbon nanotube(CNT)buckypaper enhanced using MXenes(Ti3C2Tx)for high-performance EMI shielding is synthesized through a facile electrophoretic deposition process.The obtained Ti3C2Tx@CNT hybrid buckypaper exhibits an outstanding EMI SE of 60.5 dB in the X-band at 100μm.The hybrid buckypaper with an MXene content of 49.4 wt%exhibits an EMI SE of 50.4 dB in the X-band with a thickness of only 15μm,which is 105%higher than that of pristine CNT buckypaper.Furthermore,an average specific SE value of 5.7×10^(4) dB cm^(2) g^(−1) is exhibited in the 5-μm hybrid buckypaper.Thus,this assembly process proves promising for the construction of ultrathin,flexible,and high-performance EMI shielding films for application in electronic devices and wireless communications.
基金financially supported by the National Natural Science Foundation of China(Nos.51661145025,51972039,and 51803018)
文摘High-purity(99%)carbon nanocoils(CNCs)have been synthesized by using porousα-Fe2O3/SnO2 catalyst.The yield of CNCs reaches 9,098%after a 6 h growth.This value is much higher than the previously reported data,indicating that this method is promising to synthesize high-purity CNCs on a large scale.It is considered that an appropriate proportion of Fe and Sn,proper particle size distribution,and a loose-porous aggregate structure of the catalyst are the key points to the high-purity growth of CNCs.Benefiting from the high-purity preparation,a CNC Buckypaper was successfully prepared and the electrical,mechanical,and electrochemical properties were investigated comprehensively.Furthermore,as one of the practical applications,the CNC Buckypaper was successfully utilized as an efficient adsorbent for the removal of methylene blue dye from wastewater with an adsorption efficiency of 90.9%.This study provides a facile and economical route for preparing high-purity CNCs,which is suitable for large-quantity production.Furthermore,the fabrication of macroscopic CNC Buckypaper provides promising alternative of adsorbent or other practical applications.
基金conducted by Nanomaterials for Energy and Energy-Water Nexus(NEW)Programme under Singapore-HUJ Alliance for Research and Enterprise(SHARE)in the Campus for Research Excellence and Technological Enterprise(CREATE)that is supported by the National Research Foundation,Prime Minister’s O ce,Singaporesupported also by the Israel National Research Center for Electrochemical Propulsion(INREP)。
文摘Lithium-sulfur batteries(LSBs)are considered as the next generation of advanced rechargeable batteries because of their high energy density.In this study,sulfur and CoxS electrocatalyst are deposited on carbon nanotube buckypaper(S/CoxS/BP)by a facile electrodeposition method and are used as a binder-free high-performance cathode for LSBs.Elemental sulfur is deposited on buckypaper by electrooxidation of a polysulfide solution(-S6^2-).This approach substantially increased the current and time efficiency of sulfur electrochemical deposition on conductive material for LSBs.S/CoxS/BP cathode could deliver an initial discharge capacity as high as 1650 mAh g^-1 at 0.1 C,which is close to the theoretical capacity of sulfur.At current rate of 0.5 C,the S/CoxS/BP has a capacity of 1420 mAh g^-1 at the first cycle and 715 mAh g^-1 after 500 cycles with a fading rate of 0.099%per cycle.The high capacity of S/CoxS/BP is attributed to both the homogeneous dispersion of nanosized sulfur within BP and the presence of CoxS catalyst.The sodium dodecyl sulfate(SDS)pretreatment of BP renders it polarity to bind polysulfides and thus facilitates the good dispersibility of nanosized sulfur within BP.CoxS catalyst accelerates the kinetics of polysulfide conversion and reduces the presence of polysulfide in the cathode,which suppresses the polysulfide diffusion to anode,i.e.,the shuttle effect.The mitigation of the active material loss improves not only the capacity but also the cyclability of S/CoxS/BP.
文摘The electrical conductivity of carbon nanotube buckypapers can be dramatically increased by incorporation of silver particles contained in a commercial silver paste.Two methods,co-dispersion during the production of buckypaper and surface coating on a preformed buckypaper,were used to prepare composite buckypapers.The two types of composite buckypapers exhibited very different electrical conductivity profiles.The composite buckypapers prepared by the surface coating method showed a distinct step transition in electrical conductivity at 3 vol%silver content,leading to a 15-fold improvement at 6%silver content.The composite buckypapers prepared by the co-dispersion method showed a gradual change in electrical conductivity with increasing silver particle content,resulting in a five-fold improvement at12%silver content.Surface and sectional morphologies of the two types of composite buckypapers were examined and related to their electrical conductivity profiles.
基金This work was supported by the National Natural Science Foundation of China[11902204]Natural Science Foundation of Liaoning Province[2020-MS-236,2019010256-JH3/301]+1 种基金Shenyang Youth Technological Innovation Talent Project[RC200030,RC190004]Aeronautical Science Foundation[201903054001].
文摘Fiber-reinforced resin-based plastics are widely used in structural composites for aerospace and automotive applications,and they often face extreme load conditions in actual working environments.It is challenging to monitor the damage of the structure during the vibration process.This study was aimed at using buckypaper(BP)sensors to monitor the structural health status of composite structures under ambient vibrations.First,the feasibility of flexible printed circuit instead of wire is verified by the tensile experiment.Then the vibration monitoring experiment of the composite cantilever beam is carried out by using BP sensors systematically.The sweep frequency experiment determines the excitation frequency of the cantilever beam.Low-period vibration fatigue cycle and high-period vibration fatigue cycle experiments are designed to verify the vibration monitoring method using BP sensors.Besides,the signal response of BP sensors in the vibration experiment is analyzed,and the relationship betweenΔR/R0 and vibration acceleration is obtained.Finally,through the change law ofΔR/R0 of the sensor,the cumulative damage caused by vibration fatigue is visualized.It is demonstrated that the monitoring method based on BP sensors can be applied to study the damage behavior of composite structure under the vibration environment.
