Metal-organic frameworks(MOFs)have attracted significant interest as self-templates and precursors for the synthesis of carbon-based composites aimed at electromagnetic wave(EMW)absorption.However,the utilization of h...Metal-organic frameworks(MOFs)have attracted significant interest as self-templates and precursors for the synthesis of carbon-based composites aimed at electromagnetic wave(EMW)absorption.However,the utilization of high-temperature treatments has introduced uncertainties regarding the compositions and microstructures of resulting derivatives.Additionally,complete carbonization has led to diminished yields of the produced carbon composites,significantly limiting their practical applications.Consequently,the exploration of pristine MOF-based EMW absorbers presents an intriguing yet challenging endeavor,primarily due to inherently low electrical conductivity.In this study,we showcase the utilization of structurally robust Zr-MOFs as scaffolds to build highly conductive Zr-MOF/PPy composites via an inner-outer dual-modification approach,which involves the production of conducting polypyrrole(PPy)both within the confined nanoporous channels and the external surface of Zr-MOFs via post-synthetic modification.The interconnection of confined PPy and surface-lined PPy together leads to a consecutive and extensive conducting network to the maximum extent.This therefore entails outstanding conductivity up to~14.3 S cm^(-1) in Zr-MOF/PPy composites,which is approximately 1-2 orders of magnitude higher than that for conductive MOF nanocomposites constructed from either inner or outer modification.Benefiting from the strong and tunable conduction loss,as well as the induced dielectric polarization originated from the porous structures and MOF-polymer interfaces,Zr-MOF/PPy exhibits excellent microwave attenuation capabilities and a tunable absorption frequency range.Specifically,with only 15 wt.%loading,the minimum reflection loss(RLmin)can reach up to-67.4 dB,accompanied by an effective absorption bandwidth(EAB)extending to 6.74 GHz.Furthermore,the microwave absorption characteristics can be tailored from the C-band to the Ku-band by adjusting the loading of PPy.This work provides valuable insights into the fabrication of conductive MOF composites by presenting a straightforward pathway to enhance and reg-ulate electrical conduction in MOF-based nanocomposites,thus paving a way to facilely fabricate pristine MOF-based microwave absorbers.展开更多
Rechargeable proton batteries have been regarded as a promising technology for next-generation energy storage devices,due to the smallest size,lightest weight,ultrafast diffusion kinetics and negligible cost of proton...Rechargeable proton batteries have been regarded as a promising technology for next-generation energy storage devices,due to the smallest size,lightest weight,ultrafast diffusion kinetics and negligible cost of proton as charge carriers.Nevertheless,a proton battery possessing both high energy and power density is yet achieved.In addition,poor cycling stability is another major challenge making the lifespan of proton batteries unsatisfactory.These issues have motivated extensive research into electrode materials.Nonetheless,the design of electrode–electrolyte interphase and electrolytes is underdeveloped for solving the challenges.In this review,we summarize the development of interphase and electrolytes for proton batteries and elaborate on their importance in enhancing the energy density,power density and battery lifespan.The fundamental understanding of interphase is reviewed with respect to the desolvation process,interfacial reaction kinetics,solvent-electrode interactions,and analysis techniques.We categorize the currently used electrolytes according to their physicochemical properties and analyze their electrochemical potential window,solvent(e.g.,water)activities,ionic conductivity,thermal stability,and safety.Finally,we offer our views on the challenges and opportunities toward the future research for both interphase and electrolytes for achieving high-performance proton batteries for energy storage.展开更多
Lithium-rich layered oxides(LrLOs) deliver extremely high specific capacities and are considered to be promising candidates for electric vehicle and smart grid applications. However, the application of LrLOs needs fur...Lithium-rich layered oxides(LrLOs) deliver extremely high specific capacities and are considered to be promising candidates for electric vehicle and smart grid applications. However, the application of LrLOs needs further understanding of the structural complexity and dynamic evolution of monoclinic and rhombohedral phases, in order to overcome the issues including voltage decay, poor rate capability, initial irreversible capacity loss and etc. The development of aberration correction for the transmission electron microscope and concurrent progress in electron spectroscopy, have fueled rapid progress in the understanding of the mechanism of such issues. New techniques based on the transmission electron microscope are first surveyed, and the applications of these techniques for the study of the structure, migration of transition metal, and the activation of oxygen of LrLOs are then explored in detail, with a particular focus on the mechanism of voltage decay.展开更多
Graphene has been widely used for electrical energy storage and its performances could be further improved by heteroatom doping.How to prepare doped graphene efficiently and economically remains a significant challeng...Graphene has been widely used for electrical energy storage and its performances could be further improved by heteroatom doping.How to prepare doped graphene efficiently and economically remains a significant challenge.Here,we propose a flash-assisted doping method to produce nitrogen-and sulfur-doped graphene(N-rGO and S-rGO).Using this method,graphene oxide(GO)is reduced to few-layer graphene(rGO)in seconds without the use of reductants,accompanied with a high doping efficiency.Particularly,the as-synthesized N-rGO with a high N content of 12.75 at.%used as potassium-ion battery(KIB)anode exhibits ultrafast K+-transport kinetics and superior K^(+)-storage capability.Quantitative kinetics analysis and theoretical simulation are used to reveal the mechanism of transportation and storage of K^(+)in N-rGO.展开更多
The electrochemical nitrate reduction reaction(NO_(3)RR)holds promise for ecofriendly nitrate removal.However,the challenge of achieving high selectivity and efficiency in electrocatalyst systems still significantly h...The electrochemical nitrate reduction reaction(NO_(3)RR)holds promise for ecofriendly nitrate removal.However,the challenge of achieving high selectivity and efficiency in electrocatalyst systems still significantly hampers the mechanism understanding and the large-scale application.Tandem catalysts,comprising multiple catalytic components working synergistically,offer promising potential for improving the efficiency and selectivity of the NO3RR.This review highlights recent progress in designing tandem catalysts for electrochemical NO_(3)RR,including the noble metal-related system,transition metal electrocatalysts,and pulsed electrocatalysis strategies.Specifically,the optimization of active sites,interface engineering,synergistic effects between catalyst components,various in situ technologies,and theory simulations are discussed in detail.Challenges and opportunities in the development of tandem catalysts for scaling up electrochemical NO_(3)RR are further discussed,such as stability,durability,and reaction mechanisms.By outlining possible solutions for future tandem catalyst design,this review aims to open avenues for efficient nitrate reduction and comprehensive insights into the mechanisms for energy sustainability and environmental safety.展开更多
基金supported by the Fundamental Research Funds for the Central Universities(Nos.2232023D-01 and 2232023D-07)the Shanghai Science&Technology Committee(No.22ZR1403300)the National Natural Science Foundation of China(No.52372040).
文摘Metal-organic frameworks(MOFs)have attracted significant interest as self-templates and precursors for the synthesis of carbon-based composites aimed at electromagnetic wave(EMW)absorption.However,the utilization of high-temperature treatments has introduced uncertainties regarding the compositions and microstructures of resulting derivatives.Additionally,complete carbonization has led to diminished yields of the produced carbon composites,significantly limiting their practical applications.Consequently,the exploration of pristine MOF-based EMW absorbers presents an intriguing yet challenging endeavor,primarily due to inherently low electrical conductivity.In this study,we showcase the utilization of structurally robust Zr-MOFs as scaffolds to build highly conductive Zr-MOF/PPy composites via an inner-outer dual-modification approach,which involves the production of conducting polypyrrole(PPy)both within the confined nanoporous channels and the external surface of Zr-MOFs via post-synthetic modification.The interconnection of confined PPy and surface-lined PPy together leads to a consecutive and extensive conducting network to the maximum extent.This therefore entails outstanding conductivity up to~14.3 S cm^(-1) in Zr-MOF/PPy composites,which is approximately 1-2 orders of magnitude higher than that for conductive MOF nanocomposites constructed from either inner or outer modification.Benefiting from the strong and tunable conduction loss,as well as the induced dielectric polarization originated from the porous structures and MOF-polymer interfaces,Zr-MOF/PPy exhibits excellent microwave attenuation capabilities and a tunable absorption frequency range.Specifically,with only 15 wt.%loading,the minimum reflection loss(RLmin)can reach up to-67.4 dB,accompanied by an effective absorption bandwidth(EAB)extending to 6.74 GHz.Furthermore,the microwave absorption characteristics can be tailored from the C-band to the Ku-band by adjusting the loading of PPy.This work provides valuable insights into the fabrication of conductive MOF composites by presenting a straightforward pathway to enhance and reg-ulate electrical conduction in MOF-based nanocomposites,thus paving a way to facilely fabricate pristine MOF-based microwave absorbers.
基金award of Future Fellowship from the Australian Research Council(FT170100224)support from the UNSW Science PhD Writing Scholarship。
文摘Rechargeable proton batteries have been regarded as a promising technology for next-generation energy storage devices,due to the smallest size,lightest weight,ultrafast diffusion kinetics and negligible cost of proton as charge carriers.Nevertheless,a proton battery possessing both high energy and power density is yet achieved.In addition,poor cycling stability is another major challenge making the lifespan of proton batteries unsatisfactory.These issues have motivated extensive research into electrode materials.Nonetheless,the design of electrode–electrolyte interphase and electrolytes is underdeveloped for solving the challenges.In this review,we summarize the development of interphase and electrolytes for proton batteries and elaborate on their importance in enhancing the energy density,power density and battery lifespan.The fundamental understanding of interphase is reviewed with respect to the desolvation process,interfacial reaction kinetics,solvent-electrode interactions,and analysis techniques.We categorize the currently used electrolytes according to their physicochemical properties and analyze their electrochemical potential window,solvent(e.g.,water)activities,ionic conductivity,thermal stability,and safety.Finally,we offer our views on the challenges and opportunities toward the future research for both interphase and electrolytes for achieving high-performance proton batteries for energy storage.
基金finically supported by the National Key Research and Development Program of China (Grant No. 2016YFB0100100)Strategic Priority Research Program of Chinese Academy of Sciences (CAS, Grant No. XDA09010101)Ningbo Key Science and Technology Projects "Industrial Application Development of Graphene" (Grant No. 2014S10008)
文摘Lithium-rich layered oxides(LrLOs) deliver extremely high specific capacities and are considered to be promising candidates for electric vehicle and smart grid applications. However, the application of LrLOs needs further understanding of the structural complexity and dynamic evolution of monoclinic and rhombohedral phases, in order to overcome the issues including voltage decay, poor rate capability, initial irreversible capacity loss and etc. The development of aberration correction for the transmission electron microscope and concurrent progress in electron spectroscopy, have fueled rapid progress in the understanding of the mechanism of such issues. New techniques based on the transmission electron microscope are first surveyed, and the applications of these techniques for the study of the structure, migration of transition metal, and the activation of oxygen of LrLOs are then explored in detail, with a particular focus on the mechanism of voltage decay.
基金This work was supported by the Excellent Young Scholar Research Foundation of Sichuan University(No.2017SCU04A07)Sichuan Science and Technology Program(No.2019YFG0218).
文摘Graphene has been widely used for electrical energy storage and its performances could be further improved by heteroatom doping.How to prepare doped graphene efficiently and economically remains a significant challenge.Here,we propose a flash-assisted doping method to produce nitrogen-and sulfur-doped graphene(N-rGO and S-rGO).Using this method,graphene oxide(GO)is reduced to few-layer graphene(rGO)in seconds without the use of reductants,accompanied with a high doping efficiency.Particularly,the as-synthesized N-rGO with a high N content of 12.75 at.%used as potassium-ion battery(KIB)anode exhibits ultrafast K+-transport kinetics and superior K^(+)-storage capability.Quantitative kinetics analysis and theoretical simulation are used to reveal the mechanism of transportation and storage of K^(+)in N-rGO.
基金Shuguang Program,Grant/Award Number:22SG31National Natural Science Foundation of China,Grant/Award Numbers:52122312,52172291+1 种基金Shanghai Pujiang Program,Grant/Award Number:23PJD001China Postdoctoral Science Foundation,Grant/Award Number:2023M740584。
文摘The electrochemical nitrate reduction reaction(NO_(3)RR)holds promise for ecofriendly nitrate removal.However,the challenge of achieving high selectivity and efficiency in electrocatalyst systems still significantly hampers the mechanism understanding and the large-scale application.Tandem catalysts,comprising multiple catalytic components working synergistically,offer promising potential for improving the efficiency and selectivity of the NO3RR.This review highlights recent progress in designing tandem catalysts for electrochemical NO_(3)RR,including the noble metal-related system,transition metal electrocatalysts,and pulsed electrocatalysis strategies.Specifically,the optimization of active sites,interface engineering,synergistic effects between catalyst components,various in situ technologies,and theory simulations are discussed in detail.Challenges and opportunities in the development of tandem catalysts for scaling up electrochemical NO_(3)RR are further discussed,such as stability,durability,and reaction mechanisms.By outlining possible solutions for future tandem catalyst design,this review aims to open avenues for efficient nitrate reduction and comprehensive insights into the mechanisms for energy sustainability and environmental safety.
