Common anode materials in aqueous alkaline electrolytes,such as cadmium,metal hydrides and zinc,usually suffer from remarkable biotoxicity,high cost,and serious side reactions.To overcome these problems,we develop a c...Common anode materials in aqueous alkaline electrolytes,such as cadmium,metal hydrides and zinc,usually suffer from remarkable biotoxicity,high cost,and serious side reactions.To overcome these problems,we develop a conjugated porous polymer(CPP)in-situ grown on reduced graphene oxide(rGO)and Ketjen black(KB),noted as C_(4)N/rGO and C_(4)N/KB respectively,as the alternative anodes.The results show that C_(4)N/rGO electrode delivers a low redox potential(−0.905 V vs.Ag/AgCl),high specific capacity(268.8 mAh g^(-1) at 0.2 A g^(-1)),ultra-stable and fast sodium ion storage behavior(216 mAh g^(-1) at 20 A g^(-1))in 2 M NaOH electrolyte.The assembled C_(4)N/rGO//Ni(OH)_(2) full battery can cycle stably more than 38,000 cycles.Furthermore,by adding a small amount of antifreeze additive dimethyl sulfoxide(DMSO)to adjust the hydrogen bonding network,the low-temperature performance of the electrolyte(0.1 DMSO/2 M NaOH)is significantly improved while hydrogen evolution is inhibited.Consequently,the C_(4)N/rGO//Ni(OH)_(2) full cell exhibits an energy density of 147.3 Wh Kg^(-1) and ultra-high cycling stability over a wide temperature range from−70 to 45℃.This work provides an ultra-stable high-capacity CPPbased anode and antifreeze electrolyte for aqueous alkaline batteries and will facilitate their practical applications under extreme conditions.展开更多
The use of redox-active organic electrode materials in energy storage is restricted due to their inferior solvent resistance,abysmal conductivity,and the resultant low practical capacity.To address these issues,a clas...The use of redox-active organic electrode materials in energy storage is restricted due to their inferior solvent resistance,abysmal conductivity,and the resultant low practical capacity.To address these issues,a class of bipolar p-phenylenediimidazole-based small-molecule compounds are designed and fabricated.Theπ-conjugated backbone of these small molecules allows for electron delocalization on a big conjugation plane,endowing them with good conductivity and reaction reversibility.Furthermore,when the para-positions of phenylene are occupied by hydroxyl groups,as-formed intramolecular hydrogen bonds(N-H...O)between phenolic hydroxyl groups and the–NH groups of imidazole rings further enhance the structural planarity,resulting in higherπ-conjugation degree and better conductivity,and thus higher utilization of active sites and electrode capacity,proved by both experimental results and theoretical calculations.The optimized composite electrode DBNQ@rGO-45 shows a high specific capacity(∼308 mA h g^(−1)at 100 mA g^(−1))and a long cycling stability(112.9 mA h g^(−1)after 6000 cycles at 2000 mA g^(−1)).The significantly better electrochemical properties for hydroxyl group-containing compounds than those without hydroxyl groups attributed to intramolecular hydrogen bond-induced conjugation enhancement will inspire the structure design of organic electrodes for better energy storage.展开更多
As a promising in-situ hydrogen generation material,magnesium(Mg)has been seeking a promotion in its hydrogen generation property.Increasing the specific surface area,for example,replacing the Mg bulk using Mg powder,...As a promising in-situ hydrogen generation material,magnesium(Mg)has been seeking a promotion in its hydrogen generation property.Increasing the specific surface area,for example,replacing the Mg bulk using Mg powder,can greatly increase the hydrogen generation property,but it brings a high explosion risk,a difficulty in controlling the hydrogen generation,and an oxidation problem.In this work,we prepare a novel Mg@Ni foam material with Mg deposits on Ni foam by a physical vapor deposition method.The Ni foam not only increases the hydrolysis reaction areas of Mg by improving its specific surface area,but also kinetically accelerates the hydrolysis reaction rate of Mg by forming a uniform Mg-Ni galvanic cell.As a result,the Mg@Ni foam material realizes a near-theoretical hydrogen generation amount of Mg and a hydrogen generation rate significantly higher than those realized by the bulk Mg-based materials.The Mg@Ni foam material with the excellent hydrogen generation property is also free from explosion risk,easy to be controlled,and resistible to oxidation.A hydrogen fuel cell powered by the hydrogen generated by the Mg@Ni foam material can yield a steady voltage and run a small car for a long distance.展开更多
Two-dimensional （2D） materials generally have unusual confined electro-strong interaction in a plane and can physical and chemical properties owing to the exhibit obvious anisotropy and a significant quantum-confine...Two-dimensional （2D） materials generally have unusual confined electro-strong interaction in a plane and can physical and chemical properties owing to the exhibit obvious anisotropy and a significant quantum-confinement effect, thus showing great promise in many fields. Some 2D materials, such as graphene and MXenes, have recently exhibited extraordinary electromagnetic-wave shielding and absorbing performance, which is attributed to their special electrical behavior, large specific surface area, and low mass density. Compared with traditional microwave attenuating materials, 2D materials have several obvious inherent advantages. First, similar to other nanomaterials, 2D materials have a very large specific surface area and can provide numerous interfaces for the enhanced interfacial polarization as well as the reflection and scattering of electromagnetic waves. Second, 2D materials have a particular 2D morphology with ultrasmall thickness, which is not only beneficial for the penetration and dissipation of electromagnetic waves through the 2D nanosheets, giving rise to multiple reflections and the dissipation of electromagnetic energy, but is also conducive to the design and fabrication of various well-defined structures, such as layer-by-layer assemblies, core-shell particles, and porous foam, for broadband attenuation of electromagnetic waves. Third, owing to their good processability, 2D materials can be integrated into various multifunctional composites for multimode attenuation of electromagnetic energy. In addition to behaving as microwave reflectors and absorbers, 2D materials can act as impedance regulators and provide structural support for good impedance matching and setup of the optimal structure. Numerous studies indicate that 2D materials are among the most promising microwave attenuation materials. In view of the rapid development and enormous advancement of 2D materials in shielding and absorbing electromagnetic wave, there is a strong need to summarize the recent research results in this field for presenting a comprehensive view and providing helpful suggestions for future development.展开更多
The development of flexible capacitive pressure sensors has wide application prospects in the fields of electronic skin and intelligent wearable electronic devices,but it is still a great challenge to fabricate capaci...The development of flexible capacitive pressure sensors has wide application prospects in the fields of electronic skin and intelligent wearable electronic devices,but it is still a great challenge to fabricate capacitive sensors with high sensitivity.Few reports have considered the use of interdigital electrode structures to improve the sensitivity of capacitive pressure sensors.In this work,a new strategy for the fabrication of a high-performance capacitive flexible pressure sensor based on MXene/polyvinylpyrrolidone(PVP)by an interdigital electrode is reported.By increasing the number of interdigital electrodes and selecting the appropriate dielectric layer,the sensitivity of the capacitive sensor can be improved.The capacitive sensor based on MXene/PVP here has a high sensitivity(~1.25 kPa^(−1)),low detection limit(~0.6 Pa),wide sensing range(up to 294 kPa),fast response and recovery times(~30/15 ms)and mechanical stability of 10000 cycles.The presented sensor here can be used for various pressure detection applications,such as finger pressing,wrist pulse measuring,breathing,swallowing and speech recognition.This work provides a new method of using interdigital electrodes to fabricate a highly sensitive capacitive sensor with very promising application prospects in flexible sensors and wearable electronics.展开更多
The use of cavity to manipulate photon emission of quantum dots （QDs） has been opening unprecedented opportunities for realizing quantum functional nanophotonic devices and quantum information devices. In particular...The use of cavity to manipulate photon emission of quantum dots （QDs） has been opening unprecedented opportunities for realizing quantum functional nanophotonic devices and quantum information devices. In particular, in the field of semiconductor lasers, QDs were introduced as a superior alternative to quantum wells （QWs） to suppress the temperature dependence of the threshold current in vertical-external-cavity surfaceemitting lasers （VECSELs）. In this work, a review of properties and development of semiconductor VECSEL devices and QD laser devices is given. Based on the features of VECSEL devices, the main emphasis is put on the recent development of technological approach on semiconductor QD VECSELs. Then, from the viewpoint of both single QD nanolaser and cavity quantum electro- dynamics （QED）, a single-QD-cavity system resulting from the strong coupling of QD cavity is presented. In this review, we will cover both fundamental aspects and technological approaches of QD VECSEL devices. Lastly, the presented review here has provided deep insight into useful guideline for the development of QD VECSEL technology, future quantum functional nanophotonic devices and monolithic photonic integrated circuits （MPhlCs）.展开更多
Understanding thermal mechanisms is crucial for the selection, modification, and application of asphalt binders. Differential scanning calorimetry (DSC), a sensitive calorimetric technique, enables quantitative assess...Understanding thermal mechanisms is crucial for the selection, modification, and application of asphalt binders. Differential scanning calorimetry (DSC), a sensitive calorimetric technique, enables quantitative assessment of heat-flow responses and reveals underlying processes. This review summarizes the principles and parameter choices of conventional DSC and modulated temperature DSC, covering specimen mass, heating and cooling rates, purge gas, and baseline treatment, and outlines practical workflows for erasing or preserving thermal history, configuring thermal cycles, and implementing isothermal holds. In terms of applications, DSC determines glass transition temperature, crystallization and melting behavior, enthalpy relaxation, and heat capacity;relates thermal signatures to rheology and to performance at low and high temperatures;and investigates oxidative and thermoreversible aging through kinetic analysis. For modified binders, DSC elucidates modification mechanisms, estimates modifier content, assesses compatibility, and evaluates storage stability and the tendency toward phase separation. The technique offers high precision with small sample requirements, enabling differentiation among asphalt sources and grades, analysis of thermal history, and rapid screening. Nevertheless, limitations persist, including thermal gradients, volatilization losses, and baseline drift. Coupling with dynamic shear rheometry, thermogravimetric analysis, infrared spectroscopy, and microscopy further connects thermodynamic features to microstructure and functional performance. Future directions include establishing standardized test protocols, extracting more detailed information from DSC and linking it more directly to asphalt pavement performance, building thermal fingerprint databases for identification and quality control, and developing efficient workflows that support materials design.展开更多
基金financial support by the National Natural Science Foundation of China(22371010,21771017 and 51702009)the“Hundred Talents Program”of the Chinese Academy of Science,Fundamental Research Funds for the Central Universities,Shenzhen Science and Technology Program(JCYJ20210324115412035 JCYJ2021-0324123202008,JCYJ20210324122803009 and ZDSYS20210813095534001)Guangdong Basic and Applied Basic Research Foundation(2021A1515110880).
文摘Common anode materials in aqueous alkaline electrolytes,such as cadmium,metal hydrides and zinc,usually suffer from remarkable biotoxicity,high cost,and serious side reactions.To overcome these problems,we develop a conjugated porous polymer(CPP)in-situ grown on reduced graphene oxide(rGO)and Ketjen black(KB),noted as C_(4)N/rGO and C_(4)N/KB respectively,as the alternative anodes.The results show that C_(4)N/rGO electrode delivers a low redox potential(−0.905 V vs.Ag/AgCl),high specific capacity(268.8 mAh g^(-1) at 0.2 A g^(-1)),ultra-stable and fast sodium ion storage behavior(216 mAh g^(-1) at 20 A g^(-1))in 2 M NaOH electrolyte.The assembled C_(4)N/rGO//Ni(OH)_(2) full battery can cycle stably more than 38,000 cycles.Furthermore,by adding a small amount of antifreeze additive dimethyl sulfoxide(DMSO)to adjust the hydrogen bonding network,the low-temperature performance of the electrolyte(0.1 DMSO/2 M NaOH)is significantly improved while hydrogen evolution is inhibited.Consequently,the C_(4)N/rGO//Ni(OH)_(2) full cell exhibits an energy density of 147.3 Wh Kg^(-1) and ultra-high cycling stability over a wide temperature range from−70 to 45℃.This work provides an ultra-stable high-capacity CPPbased anode and antifreeze electrolyte for aqueous alkaline batteries and will facilitate their practical applications under extreme conditions.
基金the financial support by the National Natural Science Foundation of China (22371010, 21771017, and 51702009)the "Hundred Talents Program" of the Chinese Academy of Sciences, the Fundamental Research Funds for the Central Universities+1 种基金the Shenzhen Science and Technology Program (JCYJ20210324115412035, JCYJ2021-0324123202008, JCYJ20210 324122803009 and ZDSYS20210813095534001)the Guangdong Basic and Applied Basic Research Foundation (2021A1515110880)
文摘The use of redox-active organic electrode materials in energy storage is restricted due to their inferior solvent resistance,abysmal conductivity,and the resultant low practical capacity.To address these issues,a class of bipolar p-phenylenediimidazole-based small-molecule compounds are designed and fabricated.Theπ-conjugated backbone of these small molecules allows for electron delocalization on a big conjugation plane,endowing them with good conductivity and reaction reversibility.Furthermore,when the para-positions of phenylene are occupied by hydroxyl groups,as-formed intramolecular hydrogen bonds(N-H...O)between phenolic hydroxyl groups and the–NH groups of imidazole rings further enhance the structural planarity,resulting in higherπ-conjugation degree and better conductivity,and thus higher utilization of active sites and electrode capacity,proved by both experimental results and theoretical calculations.The optimized composite electrode DBNQ@rGO-45 shows a high specific capacity(∼308 mA h g^(−1)at 100 mA g^(−1))and a long cycling stability(112.9 mA h g^(−1)after 6000 cycles at 2000 mA g^(−1)).The significantly better electrochemical properties for hydroxyl group-containing compounds than those without hydroxyl groups attributed to intramolecular hydrogen bond-induced conjugation enhancement will inspire the structure design of organic electrodes for better energy storage.
基金support by the National Natural Science Foundation of China(21771017,51702009 and 51971157)Fundamental Research Funds for the Central Universities,Shenzhen Science and Technology Program(JCYJ20210324115412035,JCYJ20210324123202008,JCYJ20210324122803009 and ZDSYS20210813095534001)Guangdong Basic and Applied Basic Research Foundation(2021A1515110880).
文摘As a promising in-situ hydrogen generation material,magnesium(Mg)has been seeking a promotion in its hydrogen generation property.Increasing the specific surface area,for example,replacing the Mg bulk using Mg powder,can greatly increase the hydrogen generation property,but it brings a high explosion risk,a difficulty in controlling the hydrogen generation,and an oxidation problem.In this work,we prepare a novel Mg@Ni foam material with Mg deposits on Ni foam by a physical vapor deposition method.The Ni foam not only increases the hydrolysis reaction areas of Mg by improving its specific surface area,but also kinetically accelerates the hydrolysis reaction rate of Mg by forming a uniform Mg-Ni galvanic cell.As a result,the Mg@Ni foam material realizes a near-theoretical hydrogen generation amount of Mg and a hydrogen generation rate significantly higher than those realized by the bulk Mg-based materials.The Mg@Ni foam material with the excellent hydrogen generation property is also free from explosion risk,easy to be controlled,and resistible to oxidation.A hydrogen fuel cell powered by the hydrogen generated by the Mg@Ni foam material can yield a steady voltage and run a small car for a long distance.
基金This work was supported by the National Key R＆D Program of China （Grant No. 2016YFE0204200）, and the National Natural Science Foundation of China （NSFC, Grant Nos. 51702009 and 21771017）.
文摘Two-dimensional （2D） materials generally have unusual confined electro-strong interaction in a plane and can physical and chemical properties owing to the exhibit obvious anisotropy and a significant quantum-confinement effect, thus showing great promise in many fields. Some 2D materials, such as graphene and MXenes, have recently exhibited extraordinary electromagnetic-wave shielding and absorbing performance, which is attributed to their special electrical behavior, large specific surface area, and low mass density. Compared with traditional microwave attenuating materials, 2D materials have several obvious inherent advantages. First, similar to other nanomaterials, 2D materials have a very large specific surface area and can provide numerous interfaces for the enhanced interfacial polarization as well as the reflection and scattering of electromagnetic waves. Second, 2D materials have a particular 2D morphology with ultrasmall thickness, which is not only beneficial for the penetration and dissipation of electromagnetic waves through the 2D nanosheets, giving rise to multiple reflections and the dissipation of electromagnetic energy, but is also conducive to the design and fabrication of various well-defined structures, such as layer-by-layer assemblies, core-shell particles, and porous foam, for broadband attenuation of electromagnetic waves. Third, owing to their good processability, 2D materials can be integrated into various multifunctional composites for multimode attenuation of electromagnetic energy. In addition to behaving as microwave reflectors and absorbers, 2D materials can act as impedance regulators and provide structural support for good impedance matching and setup of the optimal structure. Numerous studies indicate that 2D materials are among the most promising microwave attenuation materials. In view of the rapid development and enormous advancement of 2D materials in shielding and absorbing electromagnetic wave, there is a strong need to summarize the recent research results in this field for presenting a comprehensive view and providing helpful suggestions for future development.
基金The work was supported by the‘5G+medical and health application pilot project’approved from the Ministry of Industry and Information Technology of Chinathe National Natural Science Foundation of China(NSFC Grant No.21771017)the Fundamental Research Funds for the Central Universities(YWF-21-BJ-J-313).
文摘The development of flexible capacitive pressure sensors has wide application prospects in the fields of electronic skin and intelligent wearable electronic devices,but it is still a great challenge to fabricate capacitive sensors with high sensitivity.Few reports have considered the use of interdigital electrode structures to improve the sensitivity of capacitive pressure sensors.In this work,a new strategy for the fabrication of a high-performance capacitive flexible pressure sensor based on MXene/polyvinylpyrrolidone(PVP)by an interdigital electrode is reported.By increasing the number of interdigital electrodes and selecting the appropriate dielectric layer,the sensitivity of the capacitive sensor can be improved.The capacitive sensor based on MXene/PVP here has a high sensitivity(~1.25 kPa^(−1)),low detection limit(~0.6 Pa),wide sensing range(up to 294 kPa),fast response and recovery times(~30/15 ms)and mechanical stability of 10000 cycles.The presented sensor here can be used for various pressure detection applications,such as finger pressing,wrist pulse measuring,breathing,swallowing and speech recognition.This work provides a new method of using interdigital electrodes to fabricate a highly sensitive capacitive sensor with very promising application prospects in flexible sensors and wearable electronics.
文摘The use of cavity to manipulate photon emission of quantum dots （QDs） has been opening unprecedented opportunities for realizing quantum functional nanophotonic devices and quantum information devices. In particular, in the field of semiconductor lasers, QDs were introduced as a superior alternative to quantum wells （QWs） to suppress the temperature dependence of the threshold current in vertical-external-cavity surfaceemitting lasers （VECSELs）. In this work, a review of properties and development of semiconductor VECSEL devices and QD laser devices is given. Based on the features of VECSEL devices, the main emphasis is put on the recent development of technological approach on semiconductor QD VECSELs. Then, from the viewpoint of both single QD nanolaser and cavity quantum electro- dynamics （QED）, a single-QD-cavity system resulting from the strong coupling of QD cavity is presented. In this review, we will cover both fundamental aspects and technological approaches of QD VECSEL devices. Lastly, the presented review here has provided deep insight into useful guideline for the development of QD VECSEL technology, future quantum functional nanophotonic devices and monolithic photonic integrated circuits （MPhlCs）.
基金supported by the National Natural Science Foundation of China(No.52178434).
文摘Understanding thermal mechanisms is crucial for the selection, modification, and application of asphalt binders. Differential scanning calorimetry (DSC), a sensitive calorimetric technique, enables quantitative assessment of heat-flow responses and reveals underlying processes. This review summarizes the principles and parameter choices of conventional DSC and modulated temperature DSC, covering specimen mass, heating and cooling rates, purge gas, and baseline treatment, and outlines practical workflows for erasing or preserving thermal history, configuring thermal cycles, and implementing isothermal holds. In terms of applications, DSC determines glass transition temperature, crystallization and melting behavior, enthalpy relaxation, and heat capacity;relates thermal signatures to rheology and to performance at low and high temperatures;and investigates oxidative and thermoreversible aging through kinetic analysis. For modified binders, DSC elucidates modification mechanisms, estimates modifier content, assesses compatibility, and evaluates storage stability and the tendency toward phase separation. The technique offers high precision with small sample requirements, enabling differentiation among asphalt sources and grades, analysis of thermal history, and rapid screening. Nevertheless, limitations persist, including thermal gradients, volatilization losses, and baseline drift. Coupling with dynamic shear rheometry, thermogravimetric analysis, infrared spectroscopy, and microscopy further connects thermodynamic features to microstructure and functional performance. Future directions include establishing standardized test protocols, extracting more detailed information from DSC and linking it more directly to asphalt pavement performance, building thermal fingerprint databases for identification and quality control, and developing efficient workflows that support materials design.
