Smart wearable devices are regarded to be the next prevailing technology product after smartphones and smart homes,and thus there has recently been rapid development in flexible electronic energy storage devices.Among...Smart wearable devices are regarded to be the next prevailing technology product after smartphones and smart homes,and thus there has recently been rapid development in flexible electronic energy storage devices.Among them,flexible solid-state zinc-air batteries have received widespread attention because of their high energy density,good safety,and stability.Efficient bifunctional oxygen electrocatalysts are the primary consideration in the development of flexible solid-state zinc-air batteries,and self-supported air cathodes are strong candidates because of their advantages including simplified fabrication process,reduced interfacial resistance,accelerated electron transfer,and good flexibility.This review outlines the research progress in the design and construction of nanoarray bifunctional oxygen electrocatalysts.Starting from the configuration and basic principles of zinc-air batteries and the strategies for the design of bifunctional oxygen electrocatalysts,a detailed discussion of self-supported air cathodes on carbon and metal substrates and their uses in flexible zinc-air batteries will follow.Finally,the challenges and opportunities in the development of flexible zinc-air batteries will be discussed.展开更多
Hard carbon stands out as the most promising candidate for anodes in sodium-ion battery.Nevertheless,addressing the challenges of low initial Coulombic efficiency and rate performance is crucial for practical applicat...Hard carbon stands out as the most promising candidate for anodes in sodium-ion battery.Nevertheless,addressing the challenges of low initial Coulombic efficiency and rate performance is crucial for practical applications.In this study,we employed a dimensionally designed approach,using six different biomass precursors,to preserve their inherent fine hierarchical morphological structures and appearances during the synthesis of selfsupporting carbon materials.Benefiting from its low-tortuosity structure that facilitates electron and ion transport,as well as its surface-enriched C=O functional groups and significant closed micropore areas,the obtained carbon material exhibits excellent electrochemical performance in sodium-ion storage,demonstrated by finite element simulation.Notably,the carbonized basswood exhibited a remarkable initial Coulombic efficiency of up to 92.4%and demonstrated outstanding rate performance,achieving a capacity of 223.3 mAh·g^(-1)at a high current density of2 A·g^(-1).In addition,thorough investigation was conducted on the influence of microstructure on the sodium storage behavior of hard carbon.Ex situ X-ray diffraction(XRD)was used to confirm that the capacity in the plateau region originates from interlayer insertion and closed-pore filling,which is consistent with the results obtained from smallangle X-ray scattering.These findings underscore the immense potential of leveraging surface functionalization and structural design to bolster the performance of hard carbon,paving the way for promising future advancements in this field.展开更多
High/medium entropy alloys(HEAs/MEAs)with high electrocatalytic activity have attracted great attention in water electrolysis applications.However,facile synthesis of self-supporting high/medium entropy alloys electro...High/medium entropy alloys(HEAs/MEAs)with high electrocatalytic activity have attracted great attention in water electrolysis applications.However,facile synthesis of self-supporting high/medium entropy alloys electrocatalysts with rich active sites through classical metallurgical methods is still a challenge.Here,a self-supporting porous FeCoNi MEA electrocatalyst with nanosheets-shaped surface for oxygen evolution reaction(OER)was prepared by a one-step electrochemical process from the metal oxides in molten CaCl_(2).The formation of the FeCoNi MEA is attributed to the oxides electro-reduction,high-temperature diffusion and solid solution.Additionally,the morphology and structure of the FeCoNi MEA can be precisely controlled by adjusting the electrolysis time and temperature.The electronic structure regulation and the reduced energy barrier of OER from the“cocktail effect”,the abundant exposed active sites brought by surface ultrathin nanosheets,the good electronic conductivity and electrochemical stability from the self-supporting structure enable the FeCoNi MEA electrode shows high-performance OER electrocatalysis,exhibiting a low overpotential of 233 mV at a current density of 10 mA cm^(-2),a low Tafel slope of 29.8 mV dec^(-1),and an excellent stability for over 500 h without any obvious structural destruction.This work demonstrates a facile one-step electrochemical metallurgical approach for fabricating self-supporting HEAs/MEAs electrocatalysts with nanosized surface for the application in water electrolysis.展开更多
Oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) are the key reactions in numerous renewable energy devices. Unlike conventional powdered catalysts, self-supported catalysts are extensively employed i...Oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) are the key reactions in numerous renewable energy devices. Unlike conventional powdered catalysts, self-supported catalysts are extensively employed in oxygen electrocatalysis because of the enhanced electron-transfer rate, high specific surface area, and superior mechanical flexibility. Among the self-supported conductive substrates, carbon fiber usually exhibits several distinctive advantages, such as a straightforward preparation process, relatively low cost, good stability, and excellent conductivity. Against this background,carbon fiber-based self-supported electrocatalysts have been widely applied and studied in oxygen electrocatalysis, indicating a promising development direction in oxygen electrocatalyst research.Thus, it is essential to offer an overall summary of the research progress in this field to facilitate its subsequent development. Taking the regulatory mechanisms and modification methods as a starting point, this review comprehensively summarizes recent research on carbon fiber-based self-supported electrocatalysts in recent years. Firstly, a brief overview of the synthesis methods and regulatory mechanisms of carbon fiber-based self-supported electrocatalysts is given. Furthermore, the view also highlights the modification methods and research progress of self-supported electrocatalysts synthesized on carbon fiber-based substrates in recent years in terms of different dopant atoms. Finally, the prospects for the application of self-supported electrocatalysts based on carbon fiber in oxygen electrocatalysis and the possible future directions of their development are presented. This review summarizes recent developments and applications of self-supported bi-functional electrocatalysts with carbon fiber-based materials as the conducting substrate in oxygen electrocatalysis. It also lays a robust scientific foundation for the subsequent reasonable design of highly effective carbon fiber-based self-supported electrocatalysts.展开更多
Flexible electrode design with robust structure and good performance is one of the priorities for flexible batteries to power emerging wearable electronics,and organic cathode materials have become contenders for flex...Flexible electrode design with robust structure and good performance is one of the priorities for flexible batteries to power emerging wearable electronics,and organic cathode materials have become contenders for flexible self-supporting electrodes.However,issues such as easy electrolyte solubility and low intrinsic conductivity contribute to high polarization and rapid capacity decay.Herein,we have designed a flexible self-supporting cathode based on perylene-3,4,9,10-tetracarboxylic dianhydride(PTCDA),interfacial engineering enhanced by polypyrrole(PPy),and carbon nanotubes(CNTs),forming the interconnected and flexible PTCDA/PPy/CNTs using polymerization reaction and vacuum filtration methods,effectively curbing those challenges.When used as the cathode of sodium-ion batteries,PTCDA/PPy/CNTs exhibit excellent rate capability(105.7 mAh g^(−1) at 20 C),outstanding cycling stability(79.4%capacity retention at 5 C after 500 cycles),and remarkable wide temperature application capability(86.5 mAh g^(−1) at−30℃ and 115.4 mAh g^(−1) at 60℃).The sodium storage mechanism was verified to be a reversible oxidation reaction between two Na+ions and carbonyl groups by density functional theory calculations,in situ infrared Fourier transform infrared spectroscopy,and in situ Raman spectroscopy.Surprisingly,the pouch cells based on PTCDA/PPy/CNTs exhibit good mechanical flexibility in various mechanical states.This work inspires more rational designs of flexible and self-supporting organic cathodes,promoting the development of high-performance and wide-temperature adaptable wearable electronic devices.展开更多
The majority of this research has concentrated on developing the self-support friction stir welding（SSFSW） tool which consists of a big concave upper shoulder and a small convex lower shoulder, and procedures for ma...The majority of this research has concentrated on developing the self-support friction stir welding（SSFSW） tool which consists of a big concave upper shoulder and a small convex lower shoulder, and procedures for making reliable welds in aluminum hollow extrusion. The 5-mm-thick 6082-T6 aluminum alloy was self-support friction stir welded at a constant tool rotation speed of 800 r/min. The effect of welding speed on microstructure and mechanical properties was investigated. The results of transverse tensile test indicated that the tensile strength of joints increased and the elongation decreased with increasing welding speed. The whole values of microhardness of SSFSW joints increased with increasing welding speed from 10 to 200 mm/min. The defectfree joints were obtained at lower welding speeds and the tensile fracture was located at the heat-affected zone（HAZ） adjacent to the thermo-mechanically affected zone（TMAZ） on the advancing side. The investigation of the flow pattern of the softened metal around the SSFSW tool revealed that the flow pattern of the softened metal was driven by two shoulders and the stir pin. The failure of specimens in tension presented the ductile fracture mode.展开更多
The flexible self-supporting electrode can maintain good mechanical and electrical properties while retaining high specific capacity,which meets the requirements of flexible batteries.Lithium-sulfur batteries(LSBs),as...The flexible self-supporting electrode can maintain good mechanical and electrical properties while retaining high specific capacity,which meets the requirements of flexible batteries.Lithium-sulfur batteries(LSBs),as a new generation of energy storage system,hold much higher theoretical energy density than traditional batteries,and they have attracted extensive attention from both the academic and industrial communities.Selection of a proper substrate material is important for the flexible self-supporting electrode.Carbon materials,with the advantages of light weight,high conductivity,strong structural plasticity,and low cost,provide the electrode with a large loading space for the active material and a conductive network.This makes the carbon materials meet the mechanical and electrochemical requirements of flexible electrodes.In this paper,the commonly used fabrication methods and recent research progresses of the flexible self-supporting cathode with a carbon material as the substrate are introduced.Various sulfur loading methods are summarized,which provides useful information for the structural design of the cathode.As the first review article of the carbon-based flexible self-supporting LSB cathodes,it provides valuable guidance for the researchers working in the field of LSB.展开更多
Flexible carbon fiber cloth(CFC)is an important scaffold and/or current collector for active materials in the development of flexible self-supportive electrode materials(SSEMs),especially in lithium-ion batteries.Howe...Flexible carbon fiber cloth(CFC)is an important scaffold and/or current collector for active materials in the development of flexible self-supportive electrode materials(SSEMs),especially in lithium-ion batteries.However,during the intercalation of Li ions into the matrix of CFC(below 0.5 V vs.Li/Li+),the incompatibility in the capacity of the CFC,when used directly as an anode material or as a current collector for active materials,leads to difficulty in the estimation of its actual contribution.To address this issue,we prepared Ni_(5)P_(4)nanosheets on CFC(denoted CFC@Ni_(5)P_(4))and investigated the contribution of CFC in the CFC@Ni_(5)P_(4)by comparing to the powder Ni_(5)P_(4)nanosheets traditionally coated on a copper foil(CuF)(denoted P-Ni_(5)P_(4)).At a current density of 0.4 mA cm^(−2),the as-prepared CFC@Ni_(5)P_(4)showed an areal capacity of 7.38 mAh cm^(−2),which is significantly higher than that of the PNi_(5)P_(4)electrode.More importantly,theoretical studies revealed that the CFC has a high Li adsorption energy that contributes to the low Li-ion diffusion energy barrier of the Ni_(5)P_(4)due to the strong interaction between the CFC and Ni_(5)P_(4),leading to the superior Li-ion storage performance of the CFC@Ni_(5)P_(4)over the pristine Ni_(5)P_(4)sample.This present work unveils the underlying mechanism leading to the achievement of high performance in SSEMs.展开更多
Stable non-noble metal bifunctional electrocatalysts are one of the challenges to the fluctuating overall water splitting driven by re-newable energy.Herein,a novel self-supporting hierarchically porous Ni_(x)Fe-S/NiF...Stable non-noble metal bifunctional electrocatalysts are one of the challenges to the fluctuating overall water splitting driven by re-newable energy.Herein,a novel self-supporting hierarchically porous Ni_(x)Fe-S/NiFe_(2)O_(4) heterostructure as bifunctional electrocatalyst was constructed based on porous Ni-Fe electrodeposition on three-dimensional(3D)carbon fiber cloth,in situ oxidation,and chemical sulfuration.Results showed that the Ni_(x)Fe-S/NiFe_(2)O_(4) heterostructure with a large specific surface area exhibits good bifunctional activity and stability for both hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)because of the abundance of active sites,synergistic effect of the heterostructure,superhydrophilic surface,and stable,self-supporting structure.The results further confirmed that the Ni_(x)Fe-S phase in the heterostructure is transformed into metal oxides/hydroxides and Ni_(3)S_(2) during OER.Compared with the commercial 20wt%Pt/C||IrO_(2)-Ta_(2)O_(5) electrolyzer,the self-supporting Ni1/5Fe-S/NiFe_(2)O_(4)||Ni1/2Fe-S/NiFe_(2)O_(4) electrolyzer exhibits better stability and lower cell voltage in the fluctu-ating current density range of 10-500 mA/cm^(2).Particularly,the cell voltage of Ni1/5Fe-S/NiFe_(2)O_(4)||Ni1/2Fe-S/NiFe_(2)O_(4) is only approximately 3.91 V at an industrial current density of 500 mA/cm^(2),which is lower than that of the 20wt%Pt/C||IrO_(2)-Ta_(2)O_(5) electrolyzer(i.e.,approximately 4.79 V).This work provides a promising strategy to develop excellent bifunctional electrocatalysts for fluctuating overall water splitting.展开更多
Developing effective and practical electrocatalyst under industrial electrolysis conditions is critical for renewable hydrogen production.Herein,we report the self-supporting NiFe LDH-MoS_(x)integrated electrode for w...Developing effective and practical electrocatalyst under industrial electrolysis conditions is critical for renewable hydrogen production.Herein,we report the self-supporting NiFe LDH-MoS_(x)integrated electrode for water oxidation under normal alkaline test condition(1 M KOH at 25℃)and simulated industrial electrolysis conditions(5 M KOH at 65℃).Such optimized electrode exhibits excellent oxygen evolution reaction(OER)performance with overpotential of 195 and 290 mV at current density of 100 and 400 mA·cm^(-2)under normal alkaline test condition.Notably,only over-potential of 156 and 201 mV were required to achieve the current density of 100 and 400mA·cm^(-2)under simulated industrial electrolysis conditions.No significant degradations were observed after long-term durability tests for both conditions.When using in two-electrode system,the operational voltages of 1.44 and 1.72 V were required to achieve a current density of 10 and 100 mA·cm^(-2)for the overall water splitting test(NiFe LDH-MoS_(x)/INF||20%Pt/C).Additionally,the operational voltage of employing NiFe LDH-MoS_(x)/INF as both cathode and anode merely require 1.52 V at 50mA·cm^(-2)at simulated industrial electrolysis conditions.Notably,a membrane electrode assembly(MEA)for anion exchange membrane water electrolysis(AEMWEs)using NiFe LDH-MoS_(x)/INF as an anode catalyst exhibited an energy conversion efficiency of 71.8%at current density of 400 mA·cm^(-2)in 1 M KOH at 60℃.Further experimental results reveal that sulfurized substrate not only improved the conductivity of NiFe LDH,but also regulated its electronic configurations and atomic composition,leading to the excellent activity.The easy-obtained and cost-effective integrated electrodes are expected to meet the large-scale application of industrial water electrolysis.展开更多
To meet the practical demand of wearable/portable electronics, developing high-efficiency and durable multifunctional catalyst and in-situ assembling catalysts into electrodes with flexible features are urgently neede...To meet the practical demand of wearable/portable electronics, developing high-efficiency and durable multifunctional catalyst and in-situ assembling catalysts into electrodes with flexible features are urgently needed but challenging. Herein, we report a simple route to fabricate bendable multifunctional electrodes by in-situ carbonization of metal ion absorbed polyaniline precursor. Alloy nanoparticles encapsulated in graphite layer are uniformly distributed in the N-doping carbon nanorod skeleton. Profiting from the favorable free-standing structure and the cooperative effect of metallic nanoparticles, graphitic layer and N doped-carbon architecture, the trifunctional electrodes exhibit prominent activities and stability toward HER, OER and ORR. Notably, due to the protection of carbon layer, the electrocatalysts show the reversible catalytic HER/OER properties. The overall water splitting device can continuously work for 12 h under frequent exchanges of cathode and anode. Importantly, the bendable metal air batteries fabricated by self-supported electrode not only displays the outstanding battery performance,achieving a decent peak power density(125 mW cm^(-2)) and exhibiting favorable charge-discharge durability of 22 h, but also holds superb flexible stability. Specially, a lightweight self-driven water splitting unit is demonstrated with stable hydrogen production.展开更多
Metal sulfides with high theoretical capacities are expected as promising cathode materials of Al batteries(AIBs). However, powdery active materials are mainly synthesized and loaded on current collector by insulating...Metal sulfides with high theoretical capacities are expected as promising cathode materials of Al batteries(AIBs). However, powdery active materials are mainly synthesized and loaded on current collector by insulating binder without capacity. Meanwhile, S as inert element in metal sulfides can not usually provide capacity. So, powdery metal sulfides only exhibit limiting practical capacity and poor cycling stability due to weak conductivity and low mass utilization. Herein, the novel self-supporting and dual-active Co-S nanosheets on carbon cloth (i.e. Co-S/CC) with hierarchically porous structure are constructed as cathode of AIBs. Co-S nanosheets are derived from ZIF-67 nanosheets on CC by a facile ligand replacement reaction. As a result, the binder-free Co-S/CC cathode with good conductivity delivers excellent initial discharge capacity of 383.4 m Ah g^(-1)(0.211 m Ah cm^(-2)) at current density of 200 m A g^(-1)and maintain reversible capacity of 156.9 m Ah g^(-1)(0.086 m Ah cm^(-2)) with Coulombic efficiency of 95.8% after 500 cycles,which are much higher than those of the traditional slurry-coating cathodes. Both Co and S as active elements in Co-S/CC contribute to capacity, which leads to a high mass utilization. This work provides a significant strategy for the construction of self-supporting metallic cathode for advanced high-energy density Al battery.展开更多
Due to the important role of oil source in our life,the separation of water-in-oil emulsion is urgent and necessary.Membrane seperation technology has been an efficient and widely used method in separating oil-water s...Due to the important role of oil source in our life,the separation of water-in-oil emulsion is urgent and necessary.Membrane seperation technology has been an efficient and widely used method in separating oil-water separation.Herein,we report a versatile approach to fabricate surface carbonized membranes with self-standing property from biomass-derived precursor by synergistic charring of phytic acid,arginine and filter paper.The obtained membrane exhibited superhydrophobicity in oil,excellent fouling resistance,and self-supporting ability.The membrane can be cycle-used at least 12 times with high permeation flux(up to 1380 L·m^(-2)·h^(-1))and separation efficiency(up to 99.4%).展开更多
Two-dimensional(2D)soft materials,especially in their self-supported forms,demonstrate attractive properties to realize biomimetic morphing and ultrasensitive sensing.Although extensive efforts on design of self-suppo...Two-dimensional(2D)soft materials,especially in their self-supported forms,demonstrate attractive properties to realize biomimetic morphing and ultrasensitive sensing.Although extensive efforts on design of self-supported functional membranes and integrated systems have been devoted,there still remains an unexplored regime of the combination of mechanical,electrical and surface wetting properties for specific functions.Here,we report a self-supported film featured with elastic,thin,conductive and superhydrophobic characteristics.Through a well-defined surface modification strategy,the surface wettability and mechanical sensing can be effectively balanced.The resulted film can function as a smart umbrella to achieve real-time simulated raining with diverse frequencies and intensity.In addition,the integrated umbrella can even response sensitively to the sunlight and demonstrate a positively correlation of current signals with the intensity of sun illumination.Moreover,the superhydrophobic umbrella can be further employed to realize water rescue,which can take the underwater object onto water surface,load and rapidly transport the considerable weight.More importantly,the whole process of loaded objects and water flow velocity can be precisely detected.The self-supported smart umbrella can effectively monitor the weather and realize a smart water rescue,demonstrating significant potentials in multifunctional sensing and directional actuation in the presence of water.展开更多
The integration of topology optimization(TO)and additive manufacturing(AM)technologies can create significant synergy benefits,while the lack of AM-friendly TO algorithms is a serious bottleneck for the application of...The integration of topology optimization(TO)and additive manufacturing(AM)technologies can create significant synergy benefits,while the lack of AM-friendly TO algorithms is a serious bottleneck for the application of TO in AM.In this paper,a TO method is proposed to design self-supporting structures with an explicit continuous self-supporting constraint,which can be adaptively activated and tightened during the optimization procedure.The TO procedure is suitable for various critical overhang angles(COA),which is integrated with build direction assignment to reduce performance loss.Besides,a triangular directional self-supporting constraint sensitivity filter is devised to promote the downward evolution of structures and maintain stability.Two numerical examples are presented;all the test cases have successfully converged and the optimized solutions demonstrate good manufacturability.In the meanwhile,a fully self-supporting design can be obtained with a slight cost in performance through combination with build direction assignment.展开更多
This far stern difficulhes and challenges fatal by the dev ofadn P in etna. to the bac national snon of China and the of and min the world market, China must meet the and Inainly by her own production. Using the input...This far stern difficulhes and challenges fatal by the dev ofadn P in etna. to the bac national snon of China and the of and min the world market, China must meet the and Inainly by her own production. Using the input output and system edence metal, this makesa foast abbot China’s glain output, grain and allsupport rate in the year 2030.展开更多
A self-supporting T-shaped gate(SST-gate) GaN device and process method using electron beam lithography are proposed.An AlGaN/GaN high-electron-mobility transistor(HEMT) device with a gate length of 100 nm is fabricat...A self-supporting T-shaped gate(SST-gate) GaN device and process method using electron beam lithography are proposed.An AlGaN/GaN high-electron-mobility transistor(HEMT) device with a gate length of 100 nm is fabricated by this method.The current gain cutoff frequency(f_(T)) is 60 GHz,and the maximum oscillation frequency(f_(max)) is 104 GHz.The current collapse has improved by 13% at static bias of(V_(GSQ),V_(DSQ))=(-8 V,10 V),and gate manufacturing yield has improved by 17% compared with the traditional floating T-shaped gate(FT-gate) device.展开更多
Photo-responsive cholesteric liquid crystals(CLCs)have attracted much attention in recent years due to their wide applications in filters,tun able optical lasers,dyn amic display devices,etc.However,UV light is usuall...Photo-responsive cholesteric liquid crystals(CLCs)have attracted much attention in recent years due to their wide applications in filters,tun able optical lasers,dyn amic display devices,etc.However,UV light is usually used as the exter nal stimulus source,which is not envir on ment-frie ndly enough.On the other hand,the mecha nical properties of CLCs are not strong eno ugh for these practical applications.Therefore,it still remains a challenge to endow the CLCs with visible light response and high mechanical properties at the same time.Herein,an axially chiral tetra-fluorinated binaphthyl azobenzene gelator(S-4F-AG)is synthesized.Upon 550 and 450 nm light irradiations,S-4F-AG exhibits excellent photo-switchable behaviors.Notably,the maximum con tent of c/s-isomer and its half-life are as high as 35%and 89 h in acet on itrile,respectively.A self-supporting CLC physical gel with a storage modulus around 104 Pa can be obtained when 3wt%S-4F-AG and 12wt%binaphthyl azobenzene derivative(dopant 2)are co-doped into a nematic LC host P0616A.This CLC physical gel exhibits a temperature-driven blue,green,and red reflection colors reversibly.Importantly,such three primary RGB colors can also be realized by adjusting the exposure time of 550 nm green light.This work lays a solid foundation for the applications ranging from information storage to high-tech anticounterfeit.展开更多
Designing efficient and stable non-precious metal HER(hydrogen evolution reaction)electrocatalysts with high large current density adaptability is significant for industrial application of hydrogen production by water...Designing efficient and stable non-precious metal HER(hydrogen evolution reaction)electrocatalysts with high large current density adaptability is significant for industrial application of hydrogen production by water electrolysis.Herein,a facile strategy was developed to construct a multi-phase Ni3 P-Co_(2)P-(Ni-Co)film with self-supporting hierarchically micro/nano-porous structure by using bubble template method electrodeposition of self-supporting micro-porous Ni Co P film,oxygen-free annealing for phase separation producing Ni_(3)P-Ni-Co_(2)P-Co structure,and acid etching for constructing surface nano-porous structure.The effective active sites for HER was significantly increased due to the hierarchically micro/nano-porous structure,which not only enlarged the surface roughness,but enhanced the bubble detachment by improving the hydrophilicity.Meanwhile,the HER electrolysis durability was improved benefiting from the Ni_(3)P-Co_(2)P phases with high corrosion resistance(especially in acid solution)and the self-supporting film structure without binder.Consequently,the Ni Co P-OA-AE film exhibited high HER catalytic performance,which delivered a current density of 10 m A cm^(-2)at a low overpotential of 42.9 and 39.7 m V in 1 M KOH and 0.5 M H_(2)SO_(4),respectively.It also possessed high long-term electrolysis durability,and the cell voltage of water electrolysis using self-supporting porous Ni Co P-OA-AE||Ir O_(2)-Ta_(2)O_(5) electrolyzer at 500 m A cm^(-2)for 250 h in 0.5 M H_(2)SO_(4 )is only 2.9 V.展开更多
Synthesis of zeolite LTN (“Linde Type N”) was investigated under insertion of a SiO2-rich filtration residue (FR) from waste water cleaning of the silane production. A new synthesis procedure was therefore developed...Synthesis of zeolite LTN (“Linde Type N”) was investigated under insertion of a SiO2-rich filtration residue (FR) from waste water cleaning of the silane production. A new synthesis procedure was therefore developed applying a flotation mechanism with the aim to grow LTN in form of thin membrane like sheets. Preparation starts with preactivation of FR by slurrying first in alkaline solution, followed by an addition of aluminate solution and citric acid. The latter was added as suitable chelating agent for the initiation of the flotation process. In the course of these experiments, we succeeded in synthesizing zeo-lite LTN with more or less zeolite SOD as byproduct in the form of a stable compact membrane-like layer at low temperature of 60℃. The crystallization was performed under isotherm static conditions in an open reaction system without addition of organic templates as structure directing agents (OSDA’s). FR was utilized as a total substitute of sodium silicate in all experiments and an expansive pre-treatment procedure like calcinations was not needed. Furthermore, membrane formation with LTN of usual synthesis needs chemically functionalized supports. In contrast self-supporting membranous LTN layers were grown for the first time in the present study.展开更多
基金supported by the National Natural Science Foundation of China(22072107,21872105)the Natural Science Foundation of Shanghai(23ZR1464800)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Science&Technology Commission of Shanghai Municipality(19DZ2271500)。
文摘Smart wearable devices are regarded to be the next prevailing technology product after smartphones and smart homes,and thus there has recently been rapid development in flexible electronic energy storage devices.Among them,flexible solid-state zinc-air batteries have received widespread attention because of their high energy density,good safety,and stability.Efficient bifunctional oxygen electrocatalysts are the primary consideration in the development of flexible solid-state zinc-air batteries,and self-supported air cathodes are strong candidates because of their advantages including simplified fabrication process,reduced interfacial resistance,accelerated electron transfer,and good flexibility.This review outlines the research progress in the design and construction of nanoarray bifunctional oxygen electrocatalysts.Starting from the configuration and basic principles of zinc-air batteries and the strategies for the design of bifunctional oxygen electrocatalysts,a detailed discussion of self-supported air cathodes on carbon and metal substrates and their uses in flexible zinc-air batteries will follow.Finally,the challenges and opportunities in the development of flexible zinc-air batteries will be discussed.
基金financially supported by the National Natural Science Foundation of China(Nos.32171709 and 32271791)China Postdoctoral Science Foundation(No.2023M743972)。
文摘Hard carbon stands out as the most promising candidate for anodes in sodium-ion battery.Nevertheless,addressing the challenges of low initial Coulombic efficiency and rate performance is crucial for practical applications.In this study,we employed a dimensionally designed approach,using six different biomass precursors,to preserve their inherent fine hierarchical morphological structures and appearances during the synthesis of selfsupporting carbon materials.Benefiting from its low-tortuosity structure that facilitates electron and ion transport,as well as its surface-enriched C=O functional groups and significant closed micropore areas,the obtained carbon material exhibits excellent electrochemical performance in sodium-ion storage,demonstrated by finite element simulation.Notably,the carbonized basswood exhibited a remarkable initial Coulombic efficiency of up to 92.4%and demonstrated outstanding rate performance,achieving a capacity of 223.3 mAh·g^(-1)at a high current density of2 A·g^(-1).In addition,thorough investigation was conducted on the influence of microstructure on the sodium storage behavior of hard carbon.Ex situ X-ray diffraction(XRD)was used to confirm that the capacity in the plateau region originates from interlayer insertion and closed-pore filling,which is consistent with the results obtained from smallangle X-ray scattering.These findings underscore the immense potential of leveraging surface functionalization and structural design to bolster the performance of hard carbon,paving the way for promising future advancements in this field.
基金supported by the National Natural Science Foundation of China(Nos.52022054,51974181,52004155,52004157,52374307,52304331,52334009)the National Key Research and Development Program of China(No.2022YFC2906100)+4 种基金the China Postdoctoral Science Foundation(No.2022M712023)the Science and Technology Commission of Shanghai Municipality(No.21DZ1208900)the Innovation Program of Shanghai Municipal Education Commission(No.2023ZKZD48)the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning(No.TP2019041)the“Shuguang Program”supported by the Shanghai Education Development Foundation and the Shanghai Municipal Education Commission(No.21SG42).
文摘High/medium entropy alloys(HEAs/MEAs)with high electrocatalytic activity have attracted great attention in water electrolysis applications.However,facile synthesis of self-supporting high/medium entropy alloys electrocatalysts with rich active sites through classical metallurgical methods is still a challenge.Here,a self-supporting porous FeCoNi MEA electrocatalyst with nanosheets-shaped surface for oxygen evolution reaction(OER)was prepared by a one-step electrochemical process from the metal oxides in molten CaCl_(2).The formation of the FeCoNi MEA is attributed to the oxides electro-reduction,high-temperature diffusion and solid solution.Additionally,the morphology and structure of the FeCoNi MEA can be precisely controlled by adjusting the electrolysis time and temperature.The electronic structure regulation and the reduced energy barrier of OER from the“cocktail effect”,the abundant exposed active sites brought by surface ultrathin nanosheets,the good electronic conductivity and electrochemical stability from the self-supporting structure enable the FeCoNi MEA electrode shows high-performance OER electrocatalysis,exhibiting a low overpotential of 233 mV at a current density of 10 mA cm^(-2),a low Tafel slope of 29.8 mV dec^(-1),and an excellent stability for over 500 h without any obvious structural destruction.This work demonstrates a facile one-step electrochemical metallurgical approach for fabricating self-supporting HEAs/MEAs electrocatalysts with nanosized surface for the application in water electrolysis.
基金Tianjin Natural Science Foundation (23JCYBJC00660)Tianjin Enterprise Science and Technology Commissioner Project (23YDTPJC00490)+2 种基金National Natural Science Foundation of China (52203066, 51973157, 61904123)China Postdoctoral Science Foundation Grant (2023M742135)State Key Laboratory of Membrane and Membrane Separation, Tiangong University。
文摘Oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) are the key reactions in numerous renewable energy devices. Unlike conventional powdered catalysts, self-supported catalysts are extensively employed in oxygen electrocatalysis because of the enhanced electron-transfer rate, high specific surface area, and superior mechanical flexibility. Among the self-supported conductive substrates, carbon fiber usually exhibits several distinctive advantages, such as a straightforward preparation process, relatively low cost, good stability, and excellent conductivity. Against this background,carbon fiber-based self-supported electrocatalysts have been widely applied and studied in oxygen electrocatalysis, indicating a promising development direction in oxygen electrocatalyst research.Thus, it is essential to offer an overall summary of the research progress in this field to facilitate its subsequent development. Taking the regulatory mechanisms and modification methods as a starting point, this review comprehensively summarizes recent research on carbon fiber-based self-supported electrocatalysts in recent years. Firstly, a brief overview of the synthesis methods and regulatory mechanisms of carbon fiber-based self-supported electrocatalysts is given. Furthermore, the view also highlights the modification methods and research progress of self-supported electrocatalysts synthesized on carbon fiber-based substrates in recent years in terms of different dopant atoms. Finally, the prospects for the application of self-supported electrocatalysts based on carbon fiber in oxygen electrocatalysis and the possible future directions of their development are presented. This review summarizes recent developments and applications of self-supported bi-functional electrocatalysts with carbon fiber-based materials as the conducting substrate in oxygen electrocatalysis. It also lays a robust scientific foundation for the subsequent reasonable design of highly effective carbon fiber-based self-supported electrocatalysts.
基金Shuangqiang Chen gratefully acknowledges the NationalNatural Science Foundation ofChina(21975154,22179078)Zhejiang Provincial Natural Science Founda-tion of China(LY24E020002)+3 种基金Shanghai MunicipalEducation Commission(Innovation Program:2019-01-07-00-09-E00021)the Innovative Research Team of High-level Local Universities in Shanghai.Bing Sunwould like to thank the financial support from ARCthrough the ARC Future Fellowship(FT220100561)YaoXiao would like to thank the financial support from theNatural Science Foundation of Zhejiang Province(LQ23E020002)the Wenzhou Key Scientific andTechnological Innovation Research Project(ZG2023053)
文摘Flexible electrode design with robust structure and good performance is one of the priorities for flexible batteries to power emerging wearable electronics,and organic cathode materials have become contenders for flexible self-supporting electrodes.However,issues such as easy electrolyte solubility and low intrinsic conductivity contribute to high polarization and rapid capacity decay.Herein,we have designed a flexible self-supporting cathode based on perylene-3,4,9,10-tetracarboxylic dianhydride(PTCDA),interfacial engineering enhanced by polypyrrole(PPy),and carbon nanotubes(CNTs),forming the interconnected and flexible PTCDA/PPy/CNTs using polymerization reaction and vacuum filtration methods,effectively curbing those challenges.When used as the cathode of sodium-ion batteries,PTCDA/PPy/CNTs exhibit excellent rate capability(105.7 mAh g^(−1) at 20 C),outstanding cycling stability(79.4%capacity retention at 5 C after 500 cycles),and remarkable wide temperature application capability(86.5 mAh g^(−1) at−30℃ and 115.4 mAh g^(−1) at 60℃).The sodium storage mechanism was verified to be a reversible oxidation reaction between two Na+ions and carbonyl groups by density functional theory calculations,in situ infrared Fourier transform infrared spectroscopy,and in situ Raman spectroscopy.Surprisingly,the pouch cells based on PTCDA/PPy/CNTs exhibit good mechanical flexibility in various mechanical states.This work inspires more rational designs of flexible and self-supporting organic cathodes,promoting the development of high-performance and wide-temperature adaptable wearable electronic devices.
基金supported by the National Natural Science Foundation of China (Nos. 50904020 and 50974046)the Fundamental Research Funds for the Central Universities (No. HIT. NSRIF. 2012007)
文摘The majority of this research has concentrated on developing the self-support friction stir welding（SSFSW） tool which consists of a big concave upper shoulder and a small convex lower shoulder, and procedures for making reliable welds in aluminum hollow extrusion. The 5-mm-thick 6082-T6 aluminum alloy was self-support friction stir welded at a constant tool rotation speed of 800 r/min. The effect of welding speed on microstructure and mechanical properties was investigated. The results of transverse tensile test indicated that the tensile strength of joints increased and the elongation decreased with increasing welding speed. The whole values of microhardness of SSFSW joints increased with increasing welding speed from 10 to 200 mm/min. The defectfree joints were obtained at lower welding speeds and the tensile fracture was located at the heat-affected zone（HAZ） adjacent to the thermo-mechanically affected zone（TMAZ） on the advancing side. The investigation of the flow pattern of the softened metal around the SSFSW tool revealed that the flow pattern of the softened metal was driven by two shoulders and the stir pin. The failure of specimens in tension presented the ductile fracture mode.
基金The authors acknowledge the financial support from the National Natural Science Foundation of China(Nos.21978110 and 51772126)the Natural Science Foundation of Beijing Municipal(No.L182062)+6 种基金the Talents Project of Beijing Municipal Committee Organization Department(No.2018000021223ZK21)the Yue Qi Young Scholar Project of China University of Mining&Technology(Beijing)(No.2017QN17)the Fundamental Research Funds for the Central Universities(No.2020XJJD01 and 2020YJSJD01)Jilin Province Science and Technology Department Program(Nos.20200201187JC and 20190101009JH)the"13th five‐year"Science and Technology Project of Jilin Provincial Education Department(No.JJKH20200407KJ)Jilin Province Development and Reform Commission Program(No.2020C026‐3)Jilin Province Fund for Talent Development Program(No.[2019]874).
文摘The flexible self-supporting electrode can maintain good mechanical and electrical properties while retaining high specific capacity,which meets the requirements of flexible batteries.Lithium-sulfur batteries(LSBs),as a new generation of energy storage system,hold much higher theoretical energy density than traditional batteries,and they have attracted extensive attention from both the academic and industrial communities.Selection of a proper substrate material is important for the flexible self-supporting electrode.Carbon materials,with the advantages of light weight,high conductivity,strong structural plasticity,and low cost,provide the electrode with a large loading space for the active material and a conductive network.This makes the carbon materials meet the mechanical and electrochemical requirements of flexible electrodes.In this paper,the commonly used fabrication methods and recent research progresses of the flexible self-supporting cathode with a carbon material as the substrate are introduced.Various sulfur loading methods are summarized,which provides useful information for the structural design of the cathode.As the first review article of the carbon-based flexible self-supporting LSB cathodes,it provides valuable guidance for the researchers working in the field of LSB.
基金National Natural Science Foundation of China,Grant/Award Numbers:21875292,21902188National Key Research and Development Program of China,Grant/Award Number:2019YFA0705702+2 种基金Hunan Provincial Natural Science Foundation,Grant/Award Number:2021JJ30087Natural Science Foundation of Guangdong Province,Grant/Award Number:2020A1515010798Hunan Joint International Laboratory of Advanced Materials and Technology for Clean Energy,Grant/Award Number:2020CB1007。
文摘Flexible carbon fiber cloth(CFC)is an important scaffold and/or current collector for active materials in the development of flexible self-supportive electrode materials(SSEMs),especially in lithium-ion batteries.However,during the intercalation of Li ions into the matrix of CFC(below 0.5 V vs.Li/Li+),the incompatibility in the capacity of the CFC,when used directly as an anode material or as a current collector for active materials,leads to difficulty in the estimation of its actual contribution.To address this issue,we prepared Ni_(5)P_(4)nanosheets on CFC(denoted CFC@Ni_(5)P_(4))and investigated the contribution of CFC in the CFC@Ni_(5)P_(4)by comparing to the powder Ni_(5)P_(4)nanosheets traditionally coated on a copper foil(CuF)(denoted P-Ni_(5)P_(4)).At a current density of 0.4 mA cm^(−2),the as-prepared CFC@Ni_(5)P_(4)showed an areal capacity of 7.38 mAh cm^(−2),which is significantly higher than that of the PNi_(5)P_(4)electrode.More importantly,theoretical studies revealed that the CFC has a high Li adsorption energy that contributes to the low Li-ion diffusion energy barrier of the Ni_(5)P_(4)due to the strong interaction between the CFC and Ni_(5)P_(4),leading to the superior Li-ion storage performance of the CFC@Ni_(5)P_(4)over the pristine Ni_(5)P_(4)sample.This present work unveils the underlying mechanism leading to the achievement of high performance in SSEMs.
基金financially supported by the National Natural Science Foundation of China (Nos. 51874020 and 52004022)
文摘Stable non-noble metal bifunctional electrocatalysts are one of the challenges to the fluctuating overall water splitting driven by re-newable energy.Herein,a novel self-supporting hierarchically porous Ni_(x)Fe-S/NiFe_(2)O_(4) heterostructure as bifunctional electrocatalyst was constructed based on porous Ni-Fe electrodeposition on three-dimensional(3D)carbon fiber cloth,in situ oxidation,and chemical sulfuration.Results showed that the Ni_(x)Fe-S/NiFe_(2)O_(4) heterostructure with a large specific surface area exhibits good bifunctional activity and stability for both hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)because of the abundance of active sites,synergistic effect of the heterostructure,superhydrophilic surface,and stable,self-supporting structure.The results further confirmed that the Ni_(x)Fe-S phase in the heterostructure is transformed into metal oxides/hydroxides and Ni_(3)S_(2) during OER.Compared with the commercial 20wt%Pt/C||IrO_(2)-Ta_(2)O_(5) electrolyzer,the self-supporting Ni1/5Fe-S/NiFe_(2)O_(4)||Ni1/2Fe-S/NiFe_(2)O_(4) electrolyzer exhibits better stability and lower cell voltage in the fluctu-ating current density range of 10-500 mA/cm^(2).Particularly,the cell voltage of Ni1/5Fe-S/NiFe_(2)O_(4)||Ni1/2Fe-S/NiFe_(2)O_(4) is only approximately 3.91 V at an industrial current density of 500 mA/cm^(2),which is lower than that of the 20wt%Pt/C||IrO_(2)-Ta_(2)O_(5) electrolyzer(i.e.,approximately 4.79 V).This work provides a promising strategy to develop excellent bifunctional electrocatalysts for fluctuating overall water splitting.
文摘Developing effective and practical electrocatalyst under industrial electrolysis conditions is critical for renewable hydrogen production.Herein,we report the self-supporting NiFe LDH-MoS_(x)integrated electrode for water oxidation under normal alkaline test condition(1 M KOH at 25℃)and simulated industrial electrolysis conditions(5 M KOH at 65℃).Such optimized electrode exhibits excellent oxygen evolution reaction(OER)performance with overpotential of 195 and 290 mV at current density of 100 and 400 mA·cm^(-2)under normal alkaline test condition.Notably,only over-potential of 156 and 201 mV were required to achieve the current density of 100 and 400mA·cm^(-2)under simulated industrial electrolysis conditions.No significant degradations were observed after long-term durability tests for both conditions.When using in two-electrode system,the operational voltages of 1.44 and 1.72 V were required to achieve a current density of 10 and 100 mA·cm^(-2)for the overall water splitting test(NiFe LDH-MoS_(x)/INF||20%Pt/C).Additionally,the operational voltage of employing NiFe LDH-MoS_(x)/INF as both cathode and anode merely require 1.52 V at 50mA·cm^(-2)at simulated industrial electrolysis conditions.Notably,a membrane electrode assembly(MEA)for anion exchange membrane water electrolysis(AEMWEs)using NiFe LDH-MoS_(x)/INF as an anode catalyst exhibited an energy conversion efficiency of 71.8%at current density of 400 mA·cm^(-2)in 1 M KOH at 60℃.Further experimental results reveal that sulfurized substrate not only improved the conductivity of NiFe LDH,but also regulated its electronic configurations and atomic composition,leading to the excellent activity.The easy-obtained and cost-effective integrated electrodes are expected to meet the large-scale application of industrial water electrolysis.
基金financially supported by the National Natural Science Foundation of China (Grants Nos. 51972349, U1801255 and 91963210)。
文摘To meet the practical demand of wearable/portable electronics, developing high-efficiency and durable multifunctional catalyst and in-situ assembling catalysts into electrodes with flexible features are urgently needed but challenging. Herein, we report a simple route to fabricate bendable multifunctional electrodes by in-situ carbonization of metal ion absorbed polyaniline precursor. Alloy nanoparticles encapsulated in graphite layer are uniformly distributed in the N-doping carbon nanorod skeleton. Profiting from the favorable free-standing structure and the cooperative effect of metallic nanoparticles, graphitic layer and N doped-carbon architecture, the trifunctional electrodes exhibit prominent activities and stability toward HER, OER and ORR. Notably, due to the protection of carbon layer, the electrocatalysts show the reversible catalytic HER/OER properties. The overall water splitting device can continuously work for 12 h under frequent exchanges of cathode and anode. Importantly, the bendable metal air batteries fabricated by self-supported electrode not only displays the outstanding battery performance,achieving a decent peak power density(125 mW cm^(-2)) and exhibiting favorable charge-discharge durability of 22 h, but also holds superb flexible stability. Specially, a lightweight self-driven water splitting unit is demonstrated with stable hydrogen production.
基金supported by the National Natural Science Foundation of China (51874020 and 52004022)the Fundamental Research Funds for the Central Universities (FRF-IP-19-001)。
文摘Metal sulfides with high theoretical capacities are expected as promising cathode materials of Al batteries(AIBs). However, powdery active materials are mainly synthesized and loaded on current collector by insulating binder without capacity. Meanwhile, S as inert element in metal sulfides can not usually provide capacity. So, powdery metal sulfides only exhibit limiting practical capacity and poor cycling stability due to weak conductivity and low mass utilization. Herein, the novel self-supporting and dual-active Co-S nanosheets on carbon cloth (i.e. Co-S/CC) with hierarchically porous structure are constructed as cathode of AIBs. Co-S nanosheets are derived from ZIF-67 nanosheets on CC by a facile ligand replacement reaction. As a result, the binder-free Co-S/CC cathode with good conductivity delivers excellent initial discharge capacity of 383.4 m Ah g^(-1)(0.211 m Ah cm^(-2)) at current density of 200 m A g^(-1)and maintain reversible capacity of 156.9 m Ah g^(-1)(0.086 m Ah cm^(-2)) with Coulombic efficiency of 95.8% after 500 cycles,which are much higher than those of the traditional slurry-coating cathodes. Both Co and S as active elements in Co-S/CC contribute to capacity, which leads to a high mass utilization. This work provides a significant strategy for the construction of self-supporting metallic cathode for advanced high-energy density Al battery.
基金financially supported by the National Natural Science Foundation of China(Nos.21875147 and 51991351)the Fundamental Research Funds for the Central Universities。
文摘Due to the important role of oil source in our life,the separation of water-in-oil emulsion is urgent and necessary.Membrane seperation technology has been an efficient and widely used method in separating oil-water separation.Herein,we report a versatile approach to fabricate surface carbonized membranes with self-standing property from biomass-derived precursor by synergistic charring of phytic acid,arginine and filter paper.The obtained membrane exhibited superhydrophobicity in oil,excellent fouling resistance,and self-supporting ability.The membrane can be cycle-used at least 12 times with high permeation flux(up to 1380 L·m^(-2)·h^(-1))and separation efficiency(up to 99.4%).
基金This research was supported by the Natural Science Foundation of China(52073295,51803226)the Sino-German Mobility Program(M-0424)+2 种基金Key Research Program of Frontier Sciences,Chinese Academy of Sciences(QYZDB-SSWSLH036)Bureau of International Cooperation,Chinese Academy of Sciences(174433KYSB20170061)K.C.Wong Education Foundation(GJTD-2019-13).
文摘Two-dimensional(2D)soft materials,especially in their self-supported forms,demonstrate attractive properties to realize biomimetic morphing and ultrasensitive sensing.Although extensive efforts on design of self-supported functional membranes and integrated systems have been devoted,there still remains an unexplored regime of the combination of mechanical,electrical and surface wetting properties for specific functions.Here,we report a self-supported film featured with elastic,thin,conductive and superhydrophobic characteristics.Through a well-defined surface modification strategy,the surface wettability and mechanical sensing can be effectively balanced.The resulted film can function as a smart umbrella to achieve real-time simulated raining with diverse frequencies and intensity.In addition,the integrated umbrella can even response sensitively to the sunlight and demonstrate a positively correlation of current signals with the intensity of sun illumination.Moreover,the superhydrophobic umbrella can be further employed to realize water rescue,which can take the underwater object onto water surface,load and rapidly transport the considerable weight.More importantly,the whole process of loaded objects and water flow velocity can be precisely detected.The self-supported smart umbrella can effectively monitor the weather and realize a smart water rescue,demonstrating significant potentials in multifunctional sensing and directional actuation in the presence of water.
基金supported by the National Key Research and Development Program of China(2018YFB1106303)Scientific Research Foundation of CAUC(2017QD10S).
文摘The integration of topology optimization(TO)and additive manufacturing(AM)technologies can create significant synergy benefits,while the lack of AM-friendly TO algorithms is a serious bottleneck for the application of TO in AM.In this paper,a TO method is proposed to design self-supporting structures with an explicit continuous self-supporting constraint,which can be adaptively activated and tightened during the optimization procedure.The TO procedure is suitable for various critical overhang angles(COA),which is integrated with build direction assignment to reduce performance loss.Besides,a triangular directional self-supporting constraint sensitivity filter is devised to promote the downward evolution of structures and maintain stability.Two numerical examples are presented;all the test cases have successfully converged and the optimized solutions demonstrate good manufacturability.In the meanwhile,a fully self-supporting design can be obtained with a slight cost in performance through combination with build direction assignment.
文摘This far stern difficulhes and challenges fatal by the dev ofadn P in etna. to the bac national snon of China and the of and min the world market, China must meet the and Inainly by her own production. Using the input output and system edence metal, this makesa foast abbot China’s glain output, grain and allsupport rate in the year 2030.
基金Project supported by the National Natural Science Foundation of China(Grant No.62188102)the Natural Science Basic Research Program of Shaanxi Province,China(Grant No.2022JM-316)the Fund from the Ministry of Education of China(Grant No.8091B042112)。
文摘A self-supporting T-shaped gate(SST-gate) GaN device and process method using electron beam lithography are proposed.An AlGaN/GaN high-electron-mobility transistor(HEMT) device with a gate length of 100 nm is fabricated by this method.The current gain cutoff frequency(f_(T)) is 60 GHz,and the maximum oscillation frequency(f_(max)) is 104 GHz.The current collapse has improved by 13% at static bias of(V_(GSQ),V_(DSQ))=(-8 V,10 V),and gate manufacturing yield has improved by 17% compared with the traditional floating T-shaped gate(FT-gate) device.
文摘Photo-responsive cholesteric liquid crystals(CLCs)have attracted much attention in recent years due to their wide applications in filters,tun able optical lasers,dyn amic display devices,etc.However,UV light is usually used as the exter nal stimulus source,which is not envir on ment-frie ndly enough.On the other hand,the mecha nical properties of CLCs are not strong eno ugh for these practical applications.Therefore,it still remains a challenge to endow the CLCs with visible light response and high mechanical properties at the same time.Herein,an axially chiral tetra-fluorinated binaphthyl azobenzene gelator(S-4F-AG)is synthesized.Upon 550 and 450 nm light irradiations,S-4F-AG exhibits excellent photo-switchable behaviors.Notably,the maximum con tent of c/s-isomer and its half-life are as high as 35%and 89 h in acet on itrile,respectively.A self-supporting CLC physical gel with a storage modulus around 104 Pa can be obtained when 3wt%S-4F-AG and 12wt%binaphthyl azobenzene derivative(dopant 2)are co-doped into a nematic LC host P0616A.This CLC physical gel exhibits a temperature-driven blue,green,and red reflection colors reversibly.Importantly,such three primary RGB colors can also be realized by adjusting the exposure time of 550 nm green light.This work lays a solid foundation for the applications ranging from information storage to high-tech anticounterfeit.
基金supported by the National Natural Science Foundation of China(Nos.51804023 and 51874020)the Fundamental Research Funds for the Central Universities(Nos.FRF-TP-18-007A1)+1 种基金the China Postdoctoral Science Foundation(Nos.2019M650489 and 2019T120046)Taishan Scholars Program(No.tsqn201909087)。
文摘Designing efficient and stable non-precious metal HER(hydrogen evolution reaction)electrocatalysts with high large current density adaptability is significant for industrial application of hydrogen production by water electrolysis.Herein,a facile strategy was developed to construct a multi-phase Ni3 P-Co_(2)P-(Ni-Co)film with self-supporting hierarchically micro/nano-porous structure by using bubble template method electrodeposition of self-supporting micro-porous Ni Co P film,oxygen-free annealing for phase separation producing Ni_(3)P-Ni-Co_(2)P-Co structure,and acid etching for constructing surface nano-porous structure.The effective active sites for HER was significantly increased due to the hierarchically micro/nano-porous structure,which not only enlarged the surface roughness,but enhanced the bubble detachment by improving the hydrophilicity.Meanwhile,the HER electrolysis durability was improved benefiting from the Ni_(3)P-Co_(2)P phases with high corrosion resistance(especially in acid solution)and the self-supporting film structure without binder.Consequently,the Ni Co P-OA-AE film exhibited high HER catalytic performance,which delivered a current density of 10 m A cm^(-2)at a low overpotential of 42.9 and 39.7 m V in 1 M KOH and 0.5 M H_(2)SO_(4),respectively.It also possessed high long-term electrolysis durability,and the cell voltage of water electrolysis using self-supporting porous Ni Co P-OA-AE||Ir O_(2)-Ta_(2)O_(5) electrolyzer at 500 m A cm^(-2)for 250 h in 0.5 M H_(2)SO_(4 )is only 2.9 V.
文摘Synthesis of zeolite LTN (“Linde Type N”) was investigated under insertion of a SiO2-rich filtration residue (FR) from waste water cleaning of the silane production. A new synthesis procedure was therefore developed applying a flotation mechanism with the aim to grow LTN in form of thin membrane like sheets. Preparation starts with preactivation of FR by slurrying first in alkaline solution, followed by an addition of aluminate solution and citric acid. The latter was added as suitable chelating agent for the initiation of the flotation process. In the course of these experiments, we succeeded in synthesizing zeo-lite LTN with more or less zeolite SOD as byproduct in the form of a stable compact membrane-like layer at low temperature of 60℃. The crystallization was performed under isotherm static conditions in an open reaction system without addition of organic templates as structure directing agents (OSDA’s). FR was utilized as a total substitute of sodium silicate in all experiments and an expansive pre-treatment procedure like calcinations was not needed. Furthermore, membrane formation with LTN of usual synthesis needs chemically functionalized supports. In contrast self-supporting membranous LTN layers were grown for the first time in the present study.
