Amid the growing interest in triboelectric nanogenerators(TENGs)as novel energy-harvesting devices,several studies have focused on direct current(DC)TENGs to generate a stable DC output for operating electronic device...Amid the growing interest in triboelectric nanogenerators(TENGs)as novel energy-harvesting devices,several studies have focused on direct current(DC)TENGs to generate a stable DC output for operating electronic devices.However,owing to the working mechanisms of conventional DC TENGs,generating a stable DC output from reciprocating motion remains a challenge.Accordingly,we propose a bidirectional rotating DC TENG(BiR-TENG),which can generate DC outputs,regardless of the direction of rotation,from reciprocating motions.The distinct design of the BiR-TENG enables the mechanical rectification of the alternating current output into a rotational-direction-dependent DC output.Furthermore,it allows the conversion of the rotational-direction-dependent DC output into a unidirectional DC output by adapting the configurations depending on the rotational direction.Owing to these tailored design strategies and subsequent optimizations,the BiR-TENG could generate an effective unidirectional DC output.Applications of the BiR-TENG for the reciprocating motions of swinging doors and waves were demonstrated by harnessing this output.This study demonstrates the potential of the BiR-TENG design strategy as an effective and versatile solution for energy harvesting from reciprocating motions,highlighting the suitability of DC outputs as an energy source for electronic devices.展开更多
Triboelectricity-driven acoustic transducers with various merits have demonstrated significant potential in energy harvesting and self-powered sensing.The transducers generally require additionally a spacer and a corr...Triboelectricity-driven acoustic transducers with various merits have demonstrated significant potential in energy harvesting and self-powered sensing.The transducers generally require additionally a spacer and a corresponding exquisite process for smooth operation,which provides an unnecessary interface between the elements.The exploration of a novel manufacturing approach for triboelectricity-driven acoustic transducers is warranted to resolve this issue.Here,Triboelectricitydriven Oscillating Nano-Electricity generator(TONE)developed via mechanically guided fourdimensional(4D)printing is introduced for acoustic energy harvesting and self-powered voice recognition.The mechanically buckled structure of the TONE facilitates its smooth oscillation by sound wave without the use of an additional spacer,enabling the TONE to exhibit outputs of 156 V and 10μA.The output characteristics of the TONE are analyzed based on the acoustic-structuraltriboelectric interaction mechanism.The TONE demonstrates practical versatility by providing power to commercial electronics from controlled/daily sound and being utilized in artificial intelligence-based human voice recognition sensors.展开更多
Oxygen redox is considered a new paradigm for increasing the practical capacity and energy density of the layered oxide cathodes for Na-ion batteries. However, severe local structural changes and phase transitions dur...Oxygen redox is considered a new paradigm for increasing the practical capacity and energy density of the layered oxide cathodes for Na-ion batteries. However, severe local structural changes and phase transitions during anionic redox reactions lead to poor electrochemical performance with sluggish kinetics.Here, we propose a synergy of Li-Cu cations in harnessing the full potential of oxygen redox, through Li displacement and suppressed phase transition in P3-type layered oxide cathode. P3-type Na_(0.7)[Li_(0.1)Cu_(0.2)Mn_(0.7)]O_(2) cathode delivers a large specific capacity of ~212 mA h g^(-1)at 15 mA g^(-1). The discharge capacity is maintained up to ~90% of the initial capacity after 100 cycles, with stable occurrence of the oxygen redox in the high-voltage region. Through advanced experimental analyses and first-principles calculations, it is confirmed that a stepwise redox reaction based on Cu and O ions occurs for the charge-compensation mechanism upon charging. Based on a concrete understanding of the reaction mechanism, the Li displacement by the synergy of Li-Cu cations plays a crucial role in suppressing the structural change of the P3-type layered material under the oxygen redox reaction, and it is expected to be an effective strategy for stabilizing the oxygen redox in the layered oxides of Na-ion batteries.展开更多
Although the triboelectric nanogenerator(TENG)has been highlighted as a promising mechanical energy harvester,the requirement of stacking the two individual layers,contact and conductive layers,has been ball and chain...Although the triboelectric nanogenerator(TENG)has been highlighted as a promising mechanical energy harvester,the requirement of stacking the two individual layers,contact and conductive layers,has been ball and chain around the ankle of unleashing potential and an advantage of TENGs in their application expansion and commercialization.Herein,one-step fabrication of a single-layered bifunctional composite film-based TENG(BFTENG)driven by the sedimentation of a sol-state precursor is proposed for the extremely facile conversion of various ordinary items into energy harvesters.The BF-TENG consists of the polydimethylsiloxane(PDMS)matrix and a carbon nanopowder filler,and it includes both the dielectric part(DP)and conductive part(CP)in one single layer.The electrical percolation threshold of the incorporated concentration of carbon,ICC,for CP to act as a passage through which induced charges move in BF-TENGs is determined to be 1.0 wt%.The degree of carbon sedimentation in developing the proposed composite can be controlled by the curing speed and the probability of a crosslinking reaction.The maximum peak power is approximately 0.093μW when the contact surface area is 78.5 mm2;the contact frequency is 8 Hz,and the connected load resistance is 9 MΩ.Based on these results,the electrical performance of BF-TENGs in response to various physical stimuli is characterized considering the mechanical energy sources available in daily life.Then,converting ordinary surfaces such as desks and human skin into BF-TENGs through a single coating procedure and harvesting energy to power an electric device are demonstrated as a proof-of-concept.展开更多
Since the first invention of triboelectric nanogenerators(TENGs)in 2012,many mechanical systems have been applied to operate TENGs,but mechanical contact losses such as friction and noise are still big obstacles for i...Since the first invention of triboelectric nanogenerators(TENGs)in 2012,many mechanical systems have been applied to operate TENGs,but mechanical contact losses such as friction and noise are still big obstacles for improving their output performance and sustainability.Here,we report on a magnet-assembled cam-based TENG(MC-TENG),which has enhanced output power and sustainability by utilizing the non-contact repulsive force between the magnets.We investigate the theoretical and experimental dynamic behaviors of MC-TENGs according to the effects of the contact modes,contact and separation times,and contact forces(i.e.,pushing and repulsive forces).We suggest an optimized arrangement of magnets for the highest output performance,in which the charging time of the capacitor was 2.59 times faster than in a mechanical cam-based TENG(C-TENG).Finally,we design and demonstrate a MC-TENG-based windmill system to effectively harvest low-speed wind energy,~4 m/s,which produces very low torque.Thus,it is expected that our frictionless MC-TENG system will provide a sustainable solution for effectively harvesting a broadband of wasted mechanical energies.展开更多
Electrical stimulation has recently received attention as noninvasive treatment in skin wound healing with its outstanding biological property for clinical setting.However,the complexity of equipment for applying appr...Electrical stimulation has recently received attention as noninvasive treatment in skin wound healing with its outstanding biological property for clinical setting.However,the complexity of equipment for applying appropriate electrical stimulation remains an ongoing challenge.Here,we proposed a strategy for skin scar inhibition by providing electrical stimulation via a multilayer stacked electret(MS-electret),which can generate direct current(DC)electric field(EF)without any power supply equipment.In addition,the MS-electret can easily control the intensity of EFs by simply stacking electret layers and maintain stable EF with the surface potential of 3400 V over 5 days owing to the injected charges on the electret surface.We confirmed inhibition of type 1 collagen andα-SMA expression of human dermal fibroblasts(hDFs)by 90%and 44%in vitro,indicating that the transition of hDFs to myofibroblasts was restricted by applying stable electrical stimulation.We further revealed a 20%significant decrease in the ratio of myofibroblasts caused by the MS-electret in vivo.These findings present that the MS-electret is an outstanding candidate for effective skin scar inhibition with a battery-free,physiological electrical microenvironment,and noninvasive treatment that allows it to prevent external infection.展开更多
基金This work was supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.2022R1C1C1008831).This work was also supported by the Human Resources Development of the Korea Institute of Energy Technology Evaluation and Planning(KETEP)grant funded by the Ministry of Trade,Industry and Energy of Korea(No.RS-2023-00244330).S J P was supported by Basic Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(No.2018R1A6A1A03025526).
文摘Amid the growing interest in triboelectric nanogenerators(TENGs)as novel energy-harvesting devices,several studies have focused on direct current(DC)TENGs to generate a stable DC output for operating electronic devices.However,owing to the working mechanisms of conventional DC TENGs,generating a stable DC output from reciprocating motion remains a challenge.Accordingly,we propose a bidirectional rotating DC TENG(BiR-TENG),which can generate DC outputs,regardless of the direction of rotation,from reciprocating motions.The distinct design of the BiR-TENG enables the mechanical rectification of the alternating current output into a rotational-direction-dependent DC output.Furthermore,it allows the conversion of the rotational-direction-dependent DC output into a unidirectional DC output by adapting the configurations depending on the rotational direction.Owing to these tailored design strategies and subsequent optimizations,the BiR-TENG could generate an effective unidirectional DC output.Applications of the BiR-TENG for the reciprocating motions of swinging doors and waves were demonstrated by harnessing this output.This study demonstrates the potential of the BiR-TENG design strategy as an effective and versatile solution for energy harvesting from reciprocating motions,highlighting the suitability of DC outputs as an energy source for electronic devices.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.RS-2024-00344920)supported by the Human Resources Development of the Korea Institute of Energy Technology Evaluation and Planning(KETEP)grant funded by the Ministry of Trade,Industry and Energy of Korea(No.RS-2023-00244330)。
文摘Triboelectricity-driven acoustic transducers with various merits have demonstrated significant potential in energy harvesting and self-powered sensing.The transducers generally require additionally a spacer and a corresponding exquisite process for smooth operation,which provides an unnecessary interface between the elements.The exploration of a novel manufacturing approach for triboelectricity-driven acoustic transducers is warranted to resolve this issue.Here,Triboelectricitydriven Oscillating Nano-Electricity generator(TONE)developed via mechanically guided fourdimensional(4D)printing is introduced for acoustic energy harvesting and self-powered voice recognition.The mechanically buckled structure of the TONE facilitates its smooth oscillation by sound wave without the use of an additional spacer,enabling the TONE to exhibit outputs of 156 V and 10μA.The output characteristics of the TONE are analyzed based on the acoustic-structuraltriboelectric interaction mechanism.The TONE demonstrates practical versatility by providing power to commercial electronics from controlled/daily sound and being utilized in artificial intelligence-based human voice recognition sensors.
基金supported by the National Research Foundation of Korea grant funded by the Korea government (NRF2021R1A2C1014280)the Fundamental Research Program of the Korea Institute of Material Science (PNK9370)。
文摘Oxygen redox is considered a new paradigm for increasing the practical capacity and energy density of the layered oxide cathodes for Na-ion batteries. However, severe local structural changes and phase transitions during anionic redox reactions lead to poor electrochemical performance with sluggish kinetics.Here, we propose a synergy of Li-Cu cations in harnessing the full potential of oxygen redox, through Li displacement and suppressed phase transition in P3-type layered oxide cathode. P3-type Na_(0.7)[Li_(0.1)Cu_(0.2)Mn_(0.7)]O_(2) cathode delivers a large specific capacity of ~212 mA h g^(-1)at 15 mA g^(-1). The discharge capacity is maintained up to ~90% of the initial capacity after 100 cycles, with stable occurrence of the oxygen redox in the high-voltage region. Through advanced experimental analyses and first-principles calculations, it is confirmed that a stepwise redox reaction based on Cu and O ions occurs for the charge-compensation mechanism upon charging. Based on a concrete understanding of the reaction mechanism, the Li displacement by the synergy of Li-Cu cations plays a crucial role in suppressing the structural change of the P3-type layered material under the oxygen redox reaction, and it is expected to be an effective strategy for stabilizing the oxygen redox in the layered oxides of Na-ion batteries.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.RS-2024-00344920)supported by the Human Resources Development of the Korea Institute of Energy Technology Evaluation and Planning(KETEP)grant funded by the Ministry of Trade,Industry and Energy of Korea(No.RS2023-00244330).
文摘Although the triboelectric nanogenerator(TENG)has been highlighted as a promising mechanical energy harvester,the requirement of stacking the two individual layers,contact and conductive layers,has been ball and chain around the ankle of unleashing potential and an advantage of TENGs in their application expansion and commercialization.Herein,one-step fabrication of a single-layered bifunctional composite film-based TENG(BFTENG)driven by the sedimentation of a sol-state precursor is proposed for the extremely facile conversion of various ordinary items into energy harvesters.The BF-TENG consists of the polydimethylsiloxane(PDMS)matrix and a carbon nanopowder filler,and it includes both the dielectric part(DP)and conductive part(CP)in one single layer.The electrical percolation threshold of the incorporated concentration of carbon,ICC,for CP to act as a passage through which induced charges move in BF-TENGs is determined to be 1.0 wt%.The degree of carbon sedimentation in developing the proposed composite can be controlled by the curing speed and the probability of a crosslinking reaction.The maximum peak power is approximately 0.093μW when the contact surface area is 78.5 mm2;the contact frequency is 8 Hz,and the connected load resistance is 9 MΩ.Based on these results,the electrical performance of BF-TENGs in response to various physical stimuli is characterized considering the mechanical energy sources available in daily life.Then,converting ordinary surfaces such as desks and human skin into BF-TENGs through a single coating procedure and harvesting energy to power an electric device are demonstrated as a proof-of-concept.
基金supported by Korea Electric Power Corporation(Grant number:R18XA02)Mid-career Researcher Program(No.2019R1A2C2083934)through a National Research Foundation(NRF)of Korea.
文摘Since the first invention of triboelectric nanogenerators(TENGs)in 2012,many mechanical systems have been applied to operate TENGs,but mechanical contact losses such as friction and noise are still big obstacles for improving their output performance and sustainability.Here,we report on a magnet-assembled cam-based TENG(MC-TENG),which has enhanced output power and sustainability by utilizing the non-contact repulsive force between the magnets.We investigate the theoretical and experimental dynamic behaviors of MC-TENGs according to the effects of the contact modes,contact and separation times,and contact forces(i.e.,pushing and repulsive forces).We suggest an optimized arrangement of magnets for the highest output performance,in which the charging time of the capacitor was 2.59 times faster than in a mechanical cam-based TENG(C-TENG).Finally,we design and demonstrate a MC-TENG-based windmill system to effectively harvest low-speed wind energy,~4 m/s,which produces very low torque.Thus,it is expected that our frictionless MC-TENG system will provide a sustainable solution for effectively harvesting a broadband of wasted mechanical energies.
基金National Research Foundation of Korea(NRF),Grant/Award Numbers:2021R1A4A1032782,2022R1C1C1008831Korean Fund for Regenerative Medicine(KFRM),Grant/Award Number:21A0102L1-12Postdoctoral Research Program of Sungkyunkwan University。
文摘Electrical stimulation has recently received attention as noninvasive treatment in skin wound healing with its outstanding biological property for clinical setting.However,the complexity of equipment for applying appropriate electrical stimulation remains an ongoing challenge.Here,we proposed a strategy for skin scar inhibition by providing electrical stimulation via a multilayer stacked electret(MS-electret),which can generate direct current(DC)electric field(EF)without any power supply equipment.In addition,the MS-electret can easily control the intensity of EFs by simply stacking electret layers and maintain stable EF with the surface potential of 3400 V over 5 days owing to the injected charges on the electret surface.We confirmed inhibition of type 1 collagen andα-SMA expression of human dermal fibroblasts(hDFs)by 90%and 44%in vitro,indicating that the transition of hDFs to myofibroblasts was restricted by applying stable electrical stimulation.We further revealed a 20%significant decrease in the ratio of myofibroblasts caused by the MS-electret in vivo.These findings present that the MS-electret is an outstanding candidate for effective skin scar inhibition with a battery-free,physiological electrical microenvironment,and noninvasive treatment that allows it to prevent external infection.
