Fueled by the increasing imperative for sustainable energy solutions and the burgeoning emphasis on health awareness,self-powered techniques have undergone notable strides in advancement.Triboelectric nanogenerators(T...Fueled by the increasing imperative for sustainable energy solutions and the burgeoning emphasis on health awareness,self-powered techniques have undergone notable strides in advancement.Triboelectric nanogenerators(TENGs)stand out as a prominent device capitalizing on the principles of triboelectrification and electrostatic induction to generate electricity or electrical signals.In efforts to augment the electrical output performance of TENGs and broaden their range of applications,researchers have endeavored to refine materials,surface morphology,and structural design.Among them,physical morphological modifications play a pivotal role in enhancing the electrical properties of TENGs by increasing the contact surface area,which can be achieved by building micro-/nano-structures on the surface or inside the friction material.In this review,we summarize the common morphologies of TENGs,categorize the morphologies into surface and internal structures,and elucidate their roles in enhancing the electric output performance of devices.Moreover,we systematically classify the methodologies employed for morphological preparation into physical and chemical approaches,thereby furnishing a comprehensive survey of the diverse techniques.Subsequently,typical applications of TENGs with special morphology divided by energy harvesting and self-powered sensors are presented.Finally,an overview of the challenges and future trajectories pertinent to TENGs is conducted.Through this endeavor,the aim of this article is to catalyze the evolution of further strategies for enhancing performance of TENGs.展开更多
Owing to their high practicability,solar PV/T(photovoltaic/thermal)collectors have attracted considerable attention from researchers in both photovoltaic and solar-thermal fields worldwide.In this study,we designed an...Owing to their high practicability,solar PV/T(photovoltaic/thermal)collectors have attracted considerable attention from researchers in both photovoltaic and solar-thermal fields worldwide.In this study,we designed and constructed a novel solar-cooled PV/T system.Through experimental methods,we conducted an in-depth investigation of its thermal and electrical output characteristics and developed mathematical models for both thermal performance and electrical performance.Finally,we validated the experimental data against simulations.The results demonstrate that the designed solar-cooled PV/T system exhibits excellent thermal and electrical output performance.The utilization rate of waste heat from the PV module’s back plate reached 18.59%,and the system’s electrical efficiency improved by 1.92%compared to a conventional PV/T system.This work provides theoretical and experimental guidance for the further optimization and improvement of the solar-cooled PV/T system.展开更多
Additive manufacturing(AM),with its high flexibility,cost-effectiveness,and customization,significantly accelerates the advancement of nanogenerators,contributing to sustainable energy solutions and the Internet of Th...Additive manufacturing(AM),with its high flexibility,cost-effectiveness,and customization,significantly accelerates the advancement of nanogenerators,contributing to sustainable energy solutions and the Internet of Things.In this review,an in-depth analysis of AM for piezoelectric and triboelectric nanogenerators is presented from the perspectives of fundamental mechanisms,recent advancements,and future prospects.It highlights AM-enabled advantages of versatility across materials,structural topology optimization,microstructure design,and integrated printing,which enhance critical performance indicators of nanogenerators,such as surface charge density and piezoelectric constant,thereby improving device performance compared to conventional fabrication.Common AM techniques for nanogenerators,including fused deposition modeling,direct ink writing,stereolithography,and digital light processing,are systematically examined in terms of their working principles,improved metrics(output voltage/current,power density),theoretical explanation,and application scopes.Hierarchical relationships connecting AM technologies with performance optimization and applications of nanogenerators are elucidated,providing a solid foundation for advancements in energy harvesting,self-powered sensors,wearable devices,and human-machine interaction.Furthermore,the challenges related to fabrication quality,cross-scale manufacturing,processing efficiency,and industrial deployment are critically discussed.Finally,the future prospects of AM for nanogenerators are explored,aiming to foster continuous progress and innovation in this field.展开更多
The tribovoltaic nanogenerator(TVNG)has evolved in recent years as a novel type of nanogenerator designed to address the limitations of the standard triboelectric nanogenerator in terms of output signal and charge gen...The tribovoltaic nanogenerator(TVNG)has evolved in recent years as a novel type of nanogenerator designed to address the limitations of the standard triboelectric nanogenerator in terms of output signal and charge generation.Besides the outstanding characteristics,the tribovoltaic effect can also well be coupled with another effect to further boost the output performance.In this work,we proposed firstly a frictional heat-assisted performance enhancement in dynamic Schottky contact from the rubbing between n-type silver selenide(Ag_(2)Se)and aluminum.The chemical composition and physical characteristics of the Ag_(2)Se ceramic were analyzed using X-ray diffraction,scanning electron microscopy,and Synchrotron X-ray tomography techniques.UVeVis spectroscopy and UPS were also utilized in order to validate the semiconducting property of the n-type Ag_(2)Se ceramic.Moreover,the presence of the Schottky junction was demonstrated through the analysis of the current-bias voltage characteristic curve of the Ag_(2)Se/aluminum(Al)contact under varying stress and temperature conditions.The built-in electric field plays a crucial part in the tribovoltaic effect by efficiently transferring the excited carriers to an external load through sliding contact between Ag_(2)Se and Al.Demonstrating the synergy between tribovoltaic and thermoelectric effects becomes achievable through the excellent thermoelectric property of Ag_(2)Se.Herein,the proposed TVNG generated a peak output voltage and current of around 0.7 V and 24.8 nA,respectively,achieving a maximum output power of 12.6 nW at a load resistance of 10 kU.The influence of frictional heat on the output performance of the proposed TVNG was well demonstrated by the thermal-induced voltage and enhanced electrical output from continuous sliding.The concepts given in this study establish the basis for the progress of effective energy collection employing semiconducting materials and the advancement of flexible harvesting and sensing device development in the future.展开更多
The curved bending regions of serpentine flow channels play a crucial role in mass transfer and the overall performance of the flow field in proton exchange membrane fuel cells(PEMFCs).This paper proposes a“2D Topolo...The curved bending regions of serpentine flow channels play a crucial role in mass transfer and the overall performance of the flow field in proton exchange membrane fuel cells(PEMFCs).This paper proposes a“2D TopologyCurvature Optimization”progressive design method to optimize the bend area structures,aiming to enhance PEMFC performance.Through numerical simulations,it compares the topology-curvature optimization model with both the algorithm-based optimization model and a validation model,and analyzes the mass transfer,heat transfer characteristics,and output performance of PEMFC under different flow fields.The results indicate that the optimized structures improve convection and diffusion within the flow field,effectively enhancing the transport and distribution of oxygen and water within the PEMFC.Performance improvements,ranked from highest to lowest,are TS-III>MD-G(Model-GA)>MD-P(Model-PSO)>TS-II>TS-I.Among the optimized models,TS-III(Topology Structure-III)exhibits the greatest increases in peak current density and peak power density,with improvement of 4.72%and 3.12%,respectively.When considering the relationship between performance improvement and pressure drop using the efficiency evaluation criterion(EEC),TS-II demonstrates the best overall performance.展开更多
With widespread public attention to long-duration energy storage technologies,redox flow batteries are attracting increasing interests of researchers due to their intrinsic safety and good design flexibility.Currently...With widespread public attention to long-duration energy storage technologies,redox flow batteries are attracting increasing interests of researchers due to their intrinsic safety and good design flexibility.Currently,high capital costs are constraining the widespread commercialization of this system,which calls for the further enhancement of the output performance in its power units.The power output in a redox flow battery is greatly influenced by macro-to-micro mass transport and electrochemical reactions,which are coupled with each other and together determine the performance of the battery.Therefore,exploring how to achieve a coupled enhancement of transport and electrochemical properties rather than focusing solely on one aspect is a current area of interest.This perspective emphasizes the importance of simultaneously enhancing the transport and electrochemical properties of flow batteries and points out the challenges in this regard.展开更多
To address the limitations of traditional numerical simulation methods in determining the optimal structure parameters of thermoelectric module,such as complex modeling procedures,low computational efficiency,and poor...To address the limitations of traditional numerical simulation methods in determining the optimal structure parameters of thermoelectric module,such as complex modeling procedures,low computational efficiency,and poor adaptability to multi-objective design,this paper introduces an efficient structural optimization approach of segmented annular thermoelectric module that combines the uniformly equivalent element integral method and multi-parameter and multi-objective optimization algorithm under both constant temperature and heat flux boundary conditions.The optimization results show that the optimal resistance ratio is independent of the boundary conditions,and the optimal thermoelectric leg ratios remain approximately 1.2 across all studied cases in this study.Notably,the optimal segment ratios are highly sensitive to the temperatures at the two ends of the optimized segmented annular thermoelectric module under all conditions and can be directly calculated using the proposed fitting formulas.In addition,an optimal total thermoelectric leg angle exists for the segmented annular thermoelectric module to achieve the maximum temperature difference within the operating temperature range of the thermoelectric materials.The output power and efficiency of the optimized segmented annular thermoelectric module can be predicted using the parameter-based fitting formulas,with relative errors below 3%when compared to the direct optimization results.The proposed method in this paper offers significant advantages in terms of modeling simplicity,computational efficiency,and highly compatible with machine learning frameworks,thereby enabling artificial intelligence-assisted design and optimization pipelines for segmented annular thermoelectric modules.展开更多
In the era of the Internet of Things(IoT),the provision of sustainable power to distributed,mobile,and low-power-consumption electronic devices is a critical challenge.To overcome this challenge,the triboelectric nano...In the era of the Internet of Things(IoT),the provision of sustainable power to distributed,mobile,and low-power-consumption electronic devices is a critical challenge.To overcome this challenge,the triboelectric nanogenerator(TENG),a highly efficient high-entropy mechanical energy harvesting device,was developed in 2012.This device enables the direct conversion of irregular and low-frequency mechanical energy into pulsed alternating current(AC)signals.However,the incompatibility of most electronic devices with AC signals necessitates rectifier circuits or generators that deliver direct current(DC)signals.In recent years,DC-TENGs have undergone extensive development,achieving significant milestones in various application fields while also facing crucial challenges that require solutions.In this review,three categories of DC-TENG devices with distinct operating mechanisms are comprehensively explored:multiphase coupling,mechanical rectification,and air breakdown.Their typical structures and working mechanisms are thoroughly discussed,and specific output performance limitations,along with corresponding optimization strategies,are identified.Furthermore,the applications of DC-TENGs in various scenarios are summarized.Finally,the challenges faced by DC-TENGs and potential solutions are analyzed to guide further advancements in this technology.展开更多
基金financially supported by the Natural Science Foundation of Guangdong Province(No.2024A1515010639)PolyU Postdoc Matching Fund Scheme(No.1-W327),PolyU Grant(No.1-CE0H)+3 种基金Shenzhen Science and Technology Program(No.ZDSYS20220606100406016)Shenzhen Key Laboratory of Photonics and Biophotonics(No.ZDSYS20210623092006020)National Key Laboratory of Green and Long-Life Road Engineering in Extreme Environment(Shenzhen)(No.868-000003010103)National Natural Science Foundation of China(No.52208272)。
文摘Fueled by the increasing imperative for sustainable energy solutions and the burgeoning emphasis on health awareness,self-powered techniques have undergone notable strides in advancement.Triboelectric nanogenerators(TENGs)stand out as a prominent device capitalizing on the principles of triboelectrification and electrostatic induction to generate electricity or electrical signals.In efforts to augment the electrical output performance of TENGs and broaden their range of applications,researchers have endeavored to refine materials,surface morphology,and structural design.Among them,physical morphological modifications play a pivotal role in enhancing the electrical properties of TENGs by increasing the contact surface area,which can be achieved by building micro-/nano-structures on the surface or inside the friction material.In this review,we summarize the common morphologies of TENGs,categorize the morphologies into surface and internal structures,and elucidate their roles in enhancing the electric output performance of devices.Moreover,we systematically classify the methodologies employed for morphological preparation into physical and chemical approaches,thereby furnishing a comprehensive survey of the diverse techniques.Subsequently,typical applications of TENGs with special morphology divided by energy harvesting and self-powered sensors are presented.Finally,an overview of the challenges and future trajectories pertinent to TENGs is conducted.Through this endeavor,the aim of this article is to catalyze the evolution of further strategies for enhancing performance of TENGs.
文摘Owing to their high practicability,solar PV/T(photovoltaic/thermal)collectors have attracted considerable attention from researchers in both photovoltaic and solar-thermal fields worldwide.In this study,we designed and constructed a novel solar-cooled PV/T system.Through experimental methods,we conducted an in-depth investigation of its thermal and electrical output characteristics and developed mathematical models for both thermal performance and electrical performance.Finally,we validated the experimental data against simulations.The results demonstrate that the designed solar-cooled PV/T system exhibits excellent thermal and electrical output performance.The utilization rate of waste heat from the PV module’s back plate reached 18.59%,and the system’s electrical efficiency improved by 1.92%compared to a conventional PV/T system.This work provides theoretical and experimental guidance for the further optimization and improvement of the solar-cooled PV/T system.
基金support from the Research Committee of The Hong Kong Polytechnic University(Project codes:RMJK and 4-ZZSJ)supported by a grant from the Research Grants Council of the Hong Kong Special Administrative Region,China(Project No.PolyU15212523).
文摘Additive manufacturing(AM),with its high flexibility,cost-effectiveness,and customization,significantly accelerates the advancement of nanogenerators,contributing to sustainable energy solutions and the Internet of Things.In this review,an in-depth analysis of AM for piezoelectric and triboelectric nanogenerators is presented from the perspectives of fundamental mechanisms,recent advancements,and future prospects.It highlights AM-enabled advantages of versatility across materials,structural topology optimization,microstructure design,and integrated printing,which enhance critical performance indicators of nanogenerators,such as surface charge density and piezoelectric constant,thereby improving device performance compared to conventional fabrication.Common AM techniques for nanogenerators,including fused deposition modeling,direct ink writing,stereolithography,and digital light processing,are systematically examined in terms of their working principles,improved metrics(output voltage/current,power density),theoretical explanation,and application scopes.Hierarchical relationships connecting AM technologies with performance optimization and applications of nanogenerators are elucidated,providing a solid foundation for advancements in energy harvesting,self-powered sensors,wearable devices,and human-machine interaction.Furthermore,the challenges related to fabrication quality,cross-scale manufacturing,processing efficiency,and industrial deployment are critically discussed.Finally,the future prospects of AM for nanogenerators are explored,aiming to foster continuous progress and innovation in this field.
基金funded by King Mongkut’s University of Technology North Bangkok,Contract no.KMUTNB-67-KNOW-02by National Science,Research and Innovation Fund(NSRF)+1 种基金King Mongkut’s University of Technology North Bangkok(Project no.KMUTNBeFFe67-B-35)supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)(2021R1C1C1011588).
文摘The tribovoltaic nanogenerator(TVNG)has evolved in recent years as a novel type of nanogenerator designed to address the limitations of the standard triboelectric nanogenerator in terms of output signal and charge generation.Besides the outstanding characteristics,the tribovoltaic effect can also well be coupled with another effect to further boost the output performance.In this work,we proposed firstly a frictional heat-assisted performance enhancement in dynamic Schottky contact from the rubbing between n-type silver selenide(Ag_(2)Se)and aluminum.The chemical composition and physical characteristics of the Ag_(2)Se ceramic were analyzed using X-ray diffraction,scanning electron microscopy,and Synchrotron X-ray tomography techniques.UVeVis spectroscopy and UPS were also utilized in order to validate the semiconducting property of the n-type Ag_(2)Se ceramic.Moreover,the presence of the Schottky junction was demonstrated through the analysis of the current-bias voltage characteristic curve of the Ag_(2)Se/aluminum(Al)contact under varying stress and temperature conditions.The built-in electric field plays a crucial part in the tribovoltaic effect by efficiently transferring the excited carriers to an external load through sliding contact between Ag_(2)Se and Al.Demonstrating the synergy between tribovoltaic and thermoelectric effects becomes achievable through the excellent thermoelectric property of Ag_(2)Se.Herein,the proposed TVNG generated a peak output voltage and current of around 0.7 V and 24.8 nA,respectively,achieving a maximum output power of 12.6 nW at a load resistance of 10 kU.The influence of frictional heat on the output performance of the proposed TVNG was well demonstrated by the thermal-induced voltage and enhanced electrical output from continuous sliding.The concepts given in this study establish the basis for the progress of effective energy collection employing semiconducting materials and the advancement of flexible harvesting and sensing device development in the future.
基金supported by the National Natural Science Foundation of China(Grant No.52266018)the Doctoral Initiation Project of Xinjiang Institute of Engineering,China(No.2023XGYBQJ01)the Xinjiang Tianshan Talent-Youth Science and Technology Top Talents Project,China(No.2022TSYCCX0051)。
文摘The curved bending regions of serpentine flow channels play a crucial role in mass transfer and the overall performance of the flow field in proton exchange membrane fuel cells(PEMFCs).This paper proposes a“2D TopologyCurvature Optimization”progressive design method to optimize the bend area structures,aiming to enhance PEMFC performance.Through numerical simulations,it compares the topology-curvature optimization model with both the algorithm-based optimization model and a validation model,and analyzes the mass transfer,heat transfer characteristics,and output performance of PEMFC under different flow fields.The results indicate that the optimized structures improve convection and diffusion within the flow field,effectively enhancing the transport and distribution of oxygen and water within the PEMFC.Performance improvements,ranked from highest to lowest,are TS-III>MD-G(Model-GA)>MD-P(Model-PSO)>TS-II>TS-I.Among the optimized models,TS-III(Topology Structure-III)exhibits the greatest increases in peak current density and peak power density,with improvement of 4.72%and 3.12%,respectively.When considering the relationship between performance improvement and pressure drop using the efficiency evaluation criterion(EEC),TS-II demonstrates the best overall performance.
基金supported by the National Natural Science Founda-tion of China(no.52106265)the Natural Science Foundation of Tianjin Province,China(no.23JCZDJC01090)+1 种基金the Guangdong Major Project of Basic and Applied Basic Research(2023B0303000002)High level of special funds(G03034K001).
文摘With widespread public attention to long-duration energy storage technologies,redox flow batteries are attracting increasing interests of researchers due to their intrinsic safety and good design flexibility.Currently,high capital costs are constraining the widespread commercialization of this system,which calls for the further enhancement of the output performance in its power units.The power output in a redox flow battery is greatly influenced by macro-to-micro mass transport and electrochemical reactions,which are coupled with each other and together determine the performance of the battery.Therefore,exploring how to achieve a coupled enhancement of transport and electrochemical properties rather than focusing solely on one aspect is a current area of interest.This perspective emphasizes the importance of simultaneously enhancing the transport and electrochemical properties of flow batteries and points out the challenges in this regard.
基金support by Postdoctoral Fellowship Program of CPSF(GZC20232004)this research was funded by the National Key R&D Program of China(2023YFB4604700).
文摘To address the limitations of traditional numerical simulation methods in determining the optimal structure parameters of thermoelectric module,such as complex modeling procedures,low computational efficiency,and poor adaptability to multi-objective design,this paper introduces an efficient structural optimization approach of segmented annular thermoelectric module that combines the uniformly equivalent element integral method and multi-parameter and multi-objective optimization algorithm under both constant temperature and heat flux boundary conditions.The optimization results show that the optimal resistance ratio is independent of the boundary conditions,and the optimal thermoelectric leg ratios remain approximately 1.2 across all studied cases in this study.Notably,the optimal segment ratios are highly sensitive to the temperatures at the two ends of the optimized segmented annular thermoelectric module under all conditions and can be directly calculated using the proposed fitting formulas.In addition,an optimal total thermoelectric leg angle exists for the segmented annular thermoelectric module to achieve the maximum temperature difference within the operating temperature range of the thermoelectric materials.The output power and efficiency of the optimized segmented annular thermoelectric module can be predicted using the parameter-based fitting formulas,with relative errors below 3%when compared to the direct optimization results.The proposed method in this paper offers significant advantages in terms of modeling simplicity,computational efficiency,and highly compatible with machine learning frameworks,thereby enabling artificial intelligence-assisted design and optimization pipelines for segmented annular thermoelectric modules.
基金supported by the Postdoctoral Science Foundation(Grant No.2023M730419)the Ministry of Education“Chunhui Plan”Cooperative Scientific Research Project(Grant No.HZKY20220206)+2 种基金the Scientific and Technology Research Program of Chongqing Municipal Education Commission(Grant Nos.KJQN202100522,KJQN202200514 and KJQN202100514)the Natural Science Foundation of Chongqing(Grant No.cstc2021jcyj-msxmX0746)the Dr.“Through Train”Scientific Research Program(Grant No.CSTB2022BSXM-JCX0091)。
文摘In the era of the Internet of Things(IoT),the provision of sustainable power to distributed,mobile,and low-power-consumption electronic devices is a critical challenge.To overcome this challenge,the triboelectric nanogenerator(TENG),a highly efficient high-entropy mechanical energy harvesting device,was developed in 2012.This device enables the direct conversion of irregular and low-frequency mechanical energy into pulsed alternating current(AC)signals.However,the incompatibility of most electronic devices with AC signals necessitates rectifier circuits or generators that deliver direct current(DC)signals.In recent years,DC-TENGs have undergone extensive development,achieving significant milestones in various application fields while also facing crucial challenges that require solutions.In this review,three categories of DC-TENG devices with distinct operating mechanisms are comprehensively explored:multiphase coupling,mechanical rectification,and air breakdown.Their typical structures and working mechanisms are thoroughly discussed,and specific output performance limitations,along with corresponding optimization strategies,are identified.Furthermore,the applications of DC-TENGs in various scenarios are summarized.Finally,the challenges faced by DC-TENGs and potential solutions are analyzed to guide further advancements in this technology.
