Fast interfacial kinetics derived from bicontinuous three-dimensional(3D)architecture is a strategic feature for achieving fast-charging lithium-ion batteries(LIBs).One of the main reasons is its large active surface ...Fast interfacial kinetics derived from bicontinuous three-dimensional(3D)architecture is a strategic feature for achieving fast-charging lithium-ion batteries(LIBs).One of the main reasons is its large active surface and short diffusion path.Yet,understanding of unusual electrochemical properties still remain great challenge due to its complexity.In this study,we proposed a nickel–tin compound(Ni_(3)Sn_(4))supported by 3D Nickel scaffolds as main frame because the Ni_(3)Sn_(4) clearly offers a higher reversible capacity and stable cycling performance than bare tin(Sn).In order to verify the role of Ni,atomic-scale simulation based on density functional theory systematically addressed to the reaction mechanism and structural evolution of Ni_(3)Sn_(4) during the lithiation process.Our findings are that Ni enables Ni_(3)Sn_(4) to possess higher mechanical stability in terms of reactive flow stress,subsequently lead to improve Li storage capability.This study elucidates an understanding of the lithiation mechanism of Ni_(3)Sn_(4) and provides a new perspective for the design of high-capacity and high-power 3D anodes for fast-charging LIBs.展开更多
The application of Li metal anodes in rechargeable batteries is impeded by safety issues arising from the severe volume changes and formation of dendritic Li deposits.Three‐dimensional hollow carbon is receiving incr...The application of Li metal anodes in rechargeable batteries is impeded by safety issues arising from the severe volume changes and formation of dendritic Li deposits.Three‐dimensional hollow carbon is receiving increasing attention as a host material capable of accommodating Li metal inside its cavity;however,uncontrollable and nonuniform deposition of Li remains a challenge.In this study,we synthesize metal–organic framework‐derived carbon microcapsules with heteroatom clusters(Zn and Ag)on the capsule walls and it is demonstrated that Ag‐assisted nucleation of Li metal alters the outward‐to‐inward growth in the microcapsule host.Zn‐incorporated microcapsules are prepared via chemical etching of zeolitic imidazole framework‐8 polyhedra and are subsequently decorated with Ag by a galvanic displacement reaction between Ag^(+) and metallic Zn.Galvanically introduced Ag significantly reduces the energy barrier and increases the reaction rate for Li nucleation in the microcapsule host upon Li plating.Through combined electrochemical,microstructural,and computational studies,we verify the beneficial role of Ag‐assisted Li nucleation in facilitating inward growth inside the cavity of the microcapsule host and,in turn,enhancing electrochemical performance.This study provides new insights into the design of reversible host materials for practical Li metal batteries.展开更多
The CoCrFeMnNi high-entropy alloys(HEAs)with a(face-centered cubic) FCC structure has garnered considerable attention for its exceptional ductility and strain hardening ability.However,its yield strength is insufficie...The CoCrFeMnNi high-entropy alloys(HEAs)with a(face-centered cubic) FCC structure has garnered considerable attention for its exceptional ductility and strain hardening ability.However,its yield strength is insufficient for structural applications.In this study,strengthening mechanisms in these HEAs were investigated to gain insight into the mechanical properties according to alloy powder size.Moreover,we present a novel approach to achieve both high strength and high ductility through the creation of a bimodal structure consisting of both coarse and fine grains via gas atomization and spark plasma sintering processes.A bimodally structured HEA prepared with a mass ratio of 2:8 between coarse particles(75-106 μm) and fine particles(≤25 μm)yielded optimal results,with a strength of 491.95 MPa and elongation of 19.64%.This strength value represents an~41% increase compared with the sample that displayed a fine single microstructure(347.08 MPa for yield strength).The strength enhancement was attributed to the prevention of plastic deformation initiation from the fine particles during deformation.This innovative approach to the creation of HEAs with bimodal structures shows promise for various applications,such as structural components that require a combination of high strength and high ductility.展开更多
Multiple strain sensors are required to identify individual forces/stresses on human joints and recognize how they work together in order to determine the motion’s direction and trajectory.However,current sensors can...Multiple strain sensors are required to identify individual forces/stresses on human joints and recognize how they work together in order to determine the motion’s direction and trajectory.However,current sensors cannot detect and differentiate the individual forces/stresses and their contributions to the motion from the sensors’electrical signals.To address this critical issue,we propose a concept of unimodal tension,bend,shear,and twist strain sensors with piezoelectric poly L-lactic acid films.We then construct an integrated unimodal sensor(i-US)using the unimodal sensors and prove that the i-US can detect and differentiate individual strain modes,such as tensioning,bending,shearing,and twisting in complex motion.To demonstrate the potential impact of unimodal sensors,we design a sleeve and a glove with the i-US that can capture wrist motions and finger movements.Therefore,we expect unimodal strain sensors to provide a turning point in developing motion recognition and control systems.展开更多
Although all-inorganic perovskites possess suitable bandgap and thermal stability for photovoltaic ap-plications,the unstable film morphologies,and poor moisture stabilities lag behind the organic-inorganic hybrid cou...Although all-inorganic perovskites possess suitable bandgap and thermal stability for photovoltaic ap-plications,the unstable film morphologies,and poor moisture stabilities lag behind the organic-inorganic hybrid counterparts.Herein,we demonstrate that high qualityα-CsPbI_(2 ) Br films with improved phase sta-bility,high crystallinity,and pinhole-free film morphology was achieved by employing tetramethylammo-nium chloride(TMACl)as an additive.As a result,the TMACl-added CsPbI_(2) Br films exhibited high power conversion efficiency of 14.12%with an open-circuit voltage of 1.19 V,a short-circuit current density of 15.08 mA/cm^(2),and a fill factor of 0.78.More importantly,the TMACl addition imparts hydrophobicity to the film surface of CsPbI_(2) Br,which delivered excellent stability up to 30 days in the ambient condition and thermal stability at 85℃ for 156 h,respectively.Moreover,the TMACl-added device also exhibited excellent PCE of 27.16%under indoor light source(1000 lux),which presents a promising approach for designing stable but high performance all-inorganic perovskite solar cells.展开更多
Variations in parameters associated with the ambient environment can introduce noise in soft,body-worn sensors.For example,many piezoresistive pressure sensors exhibit a high degree of sensitivity to fluctuations in t...Variations in parameters associated with the ambient environment can introduce noise in soft,body-worn sensors.For example,many piezoresistive pressure sensors exhibit a high degree of sensitivity to fluctuations in temperature,thereby requiring active compensation strategies.The research presented here addresses this challenge with a multilayered 3D microsystem design that integrates four piezoresistive sensors in a full-Wheatstone bridge configuration.An optimized layout of the sensors relative to the neutral mechanical plane leads to both an insensitivity to temperature and an increased sensitivity to pressure,relative to previously reported devices that rely on similar operating principles.Integrating this 3D pressure sensor into a soft,flexible electronics platform yields a system capable of real-time,wireless measurements from the surface of the skin.Placement above the radial and carotid arteries yields high-quality waveforms associated with pulsatile blood flow,with quantitative correlations to blood pressure.The results establish the materials and engineering aspects of a technology with broad potential in remote health monitoring.展开更多
Continued research on the epidermal electronic sensor aims to develop sophisticated platforms that reproduce key multimodal responses in human skin,with the ability to sense various external stimuli,such as pressure,s...Continued research on the epidermal electronic sensor aims to develop sophisticated platforms that reproduce key multimodal responses in human skin,with the ability to sense various external stimuli,such as pressure,shear,torsion,and touch.The development of such applications utilizes algorithmic interpretations to analyze the complex stimulus shape,magnitude,and various moduli of the epidermis,requiring multiple complex equations for the attached sensor.In this experiment,we integrate silicon piezoresistors with a customized deep learning data process to facilitate in the precise evaluation and assessment of various stimuli without the need for such complexities.With the ability to surpass conventional vanilla deep regression models,the customized regression and classification model is capable of predicting the magnitude of the external force,epidermal hardness and object shape with an average mean absolute percentage error and accuracy of<15 and 96.9%,respectively.The technical ability of the deep learning-aided sensor and the consequent accurate data process provide important foundations for the future sensory electronic system.展开更多
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(NRF-2021M3H4A1A02045967)(NRF-2021M3H4A1A02048137)supported by the Chung-Ang University Research Scholarship Grants in 2021。
文摘Fast interfacial kinetics derived from bicontinuous three-dimensional(3D)architecture is a strategic feature for achieving fast-charging lithium-ion batteries(LIBs).One of the main reasons is its large active surface and short diffusion path.Yet,understanding of unusual electrochemical properties still remain great challenge due to its complexity.In this study,we proposed a nickel–tin compound(Ni_(3)Sn_(4))supported by 3D Nickel scaffolds as main frame because the Ni_(3)Sn_(4) clearly offers a higher reversible capacity and stable cycling performance than bare tin(Sn).In order to verify the role of Ni,atomic-scale simulation based on density functional theory systematically addressed to the reaction mechanism and structural evolution of Ni_(3)Sn_(4) during the lithiation process.Our findings are that Ni enables Ni_(3)Sn_(4) to possess higher mechanical stability in terms of reactive flow stress,subsequently lead to improve Li storage capability.This study elucidates an understanding of the lithiation mechanism of Ni_(3)Sn_(4) and provides a new perspective for the design of high-capacity and high-power 3D anodes for fast-charging LIBs.
基金National Research Foundation,Grant/Award Numbers:NRF‐2018R1A5A1025594,NRF‐2022M3J1A1062644。
文摘The application of Li metal anodes in rechargeable batteries is impeded by safety issues arising from the severe volume changes and formation of dendritic Li deposits.Three‐dimensional hollow carbon is receiving increasing attention as a host material capable of accommodating Li metal inside its cavity;however,uncontrollable and nonuniform deposition of Li remains a challenge.In this study,we synthesize metal–organic framework‐derived carbon microcapsules with heteroatom clusters(Zn and Ag)on the capsule walls and it is demonstrated that Ag‐assisted nucleation of Li metal alters the outward‐to‐inward growth in the microcapsule host.Zn‐incorporated microcapsules are prepared via chemical etching of zeolitic imidazole framework‐8 polyhedra and are subsequently decorated with Ag by a galvanic displacement reaction between Ag^(+) and metallic Zn.Galvanically introduced Ag significantly reduces the energy barrier and increases the reaction rate for Li nucleation in the microcapsule host upon Li plating.Through combined electrochemical,microstructural,and computational studies,we verify the beneficial role of Ag‐assisted Li nucleation in facilitating inward growth inside the cavity of the microcapsule host and,in turn,enhancing electrochemical performance.This study provides new insights into the design of reversible host materials for practical Li metal batteries.
基金financially supported by the Ministry of Trade,Industry&Energy (MOTIE,Korea)(No.20011520)Korea Institute of Energy Technology Evaluation and Planning (KETEP)(No.20217510100020)the Commercialization Promotion Agency for R&D Outcomes (COMPA)(No.1711175258)。
文摘The CoCrFeMnNi high-entropy alloys(HEAs)with a(face-centered cubic) FCC structure has garnered considerable attention for its exceptional ductility and strain hardening ability.However,its yield strength is insufficient for structural applications.In this study,strengthening mechanisms in these HEAs were investigated to gain insight into the mechanical properties according to alloy powder size.Moreover,we present a novel approach to achieve both high strength and high ductility through the creation of a bimodal structure consisting of both coarse and fine grains via gas atomization and spark plasma sintering processes.A bimodally structured HEA prepared with a mass ratio of 2:8 between coarse particles(75-106 μm) and fine particles(≤25 μm)yielded optimal results,with a strength of 491.95 MPa and elongation of 19.64%.This strength value represents an~41% increase compared with the sample that displayed a fine single microstructure(347.08 MPa for yield strength).The strength enhancement was attributed to the prevention of plastic deformation initiation from the fine particles during deformation.This innovative approach to the creation of HEAs with bimodal structures shows promise for various applications,such as structural components that require a combination of high strength and high ductility.
基金supported by the EU Horizon 2020 through project ETEXWELD-H2020-MSCA-RISE-2014 (Grant No.644268)the University of Manchester through the UMRI project-Graphene-Smart Textiles E-Healthcare Network (Grant No.AA14512)the Engineering and Physical Sciences Research Council (EPSRC)of UK (Grant EP/V057782/1).
文摘Multiple strain sensors are required to identify individual forces/stresses on human joints and recognize how they work together in order to determine the motion’s direction and trajectory.However,current sensors cannot detect and differentiate the individual forces/stresses and their contributions to the motion from the sensors’electrical signals.To address this critical issue,we propose a concept of unimodal tension,bend,shear,and twist strain sensors with piezoelectric poly L-lactic acid films.We then construct an integrated unimodal sensor(i-US)using the unimodal sensors and prove that the i-US can detect and differentiate individual strain modes,such as tensioning,bending,shearing,and twisting in complex motion.To demonstrate the potential impact of unimodal sensors,we design a sleeve and a glove with the i-US that can capture wrist motions and finger movements.Therefore,we expect unimodal strain sensors to provide a turning point in developing motion recognition and control systems.
基金supported by the Korea Electric Power Corporation (No. R20XO02-13)supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (No. 2020R1A6A1A03048004)。
文摘Although all-inorganic perovskites possess suitable bandgap and thermal stability for photovoltaic ap-plications,the unstable film morphologies,and poor moisture stabilities lag behind the organic-inorganic hybrid counterparts.Herein,we demonstrate that high qualityα-CsPbI_(2 ) Br films with improved phase sta-bility,high crystallinity,and pinhole-free film morphology was achieved by employing tetramethylammo-nium chloride(TMACl)as an additive.As a result,the TMACl-added CsPbI_(2) Br films exhibited high power conversion efficiency of 14.12%with an open-circuit voltage of 1.19 V,a short-circuit current density of 15.08 mA/cm^(2),and a fill factor of 0.78.More importantly,the TMACl addition imparts hydrophobicity to the film surface of CsPbI_(2) Br,which delivered excellent stability up to 30 days in the ambient condition and thermal stability at 85℃ for 156 h,respectively.Moreover,the TMACl-added device also exhibited excellent PCE of 27.16%under indoor light source(1000 lux),which presents a promising approach for designing stable but high performance all-inorganic perovskite solar cells.
基金supported by a grant from Kyung Hee University in 2022(KHU-20220916)。
文摘Variations in parameters associated with the ambient environment can introduce noise in soft,body-worn sensors.For example,many piezoresistive pressure sensors exhibit a high degree of sensitivity to fluctuations in temperature,thereby requiring active compensation strategies.The research presented here addresses this challenge with a multilayered 3D microsystem design that integrates four piezoresistive sensors in a full-Wheatstone bridge configuration.An optimized layout of the sensors relative to the neutral mechanical plane leads to both an insensitivity to temperature and an increased sensitivity to pressure,relative to previously reported devices that rely on similar operating principles.Integrating this 3D pressure sensor into a soft,flexible electronics platform yields a system capable of real-time,wireless measurements from the surface of the skin.Placement above the radial and carotid arteries yields high-quality waveforms associated with pulsatile blood flow,with quantitative correlations to blood pressure.The results establish the materials and engineering aspects of a technology with broad potential in remote health monitoring.
基金support of the MSIT (Ministry of Science and ICT),Korea,under the ICT Creative Consilience program (IITP-2020-0-01821)support by a National Research Foundation of Korea (NRF)grant funded by the Korea government (MSIP+5 种基金Ministry of Science,ICT&Future Planninggrant no.NRF-2021R1C1C1009410,and NRF2022R1A4A3032913)support by the Nano Material Technology Development Program (2020M3H4A1A03084600)through the National Research Foundation of Korea (NRF)funded by the Ministry of Science and ICT of Koreasupported by the Institute of Information&communications Technology Planning&Evaluation (IITP)grant funded by the Korea government (IITP-2021-0-02068)supported by the National Research Foundation of Korea (NRF)grant funded by the Korea government (MSITNRF-2018M3A7B4071110).
文摘Continued research on the epidermal electronic sensor aims to develop sophisticated platforms that reproduce key multimodal responses in human skin,with the ability to sense various external stimuli,such as pressure,shear,torsion,and touch.The development of such applications utilizes algorithmic interpretations to analyze the complex stimulus shape,magnitude,and various moduli of the epidermis,requiring multiple complex equations for the attached sensor.In this experiment,we integrate silicon piezoresistors with a customized deep learning data process to facilitate in the precise evaluation and assessment of various stimuli without the need for such complexities.With the ability to surpass conventional vanilla deep regression models,the customized regression and classification model is capable of predicting the magnitude of the external force,epidermal hardness and object shape with an average mean absolute percentage error and accuracy of<15 and 96.9%,respectively.The technical ability of the deep learning-aided sensor and the consequent accurate data process provide important foundations for the future sensory electronic system.
