Although scientists have conducted long-term and extensive studies on oxygen reduction reaction(ORR)catalyzed by metal-free carbon materials,they mainly have focused on the preparation and properties of various doped ...Although scientists have conducted long-term and extensive studies on oxygen reduction reaction(ORR)catalyzed by metal-free carbon materials,they mainly have focused on the preparation and properties of various doped carbon materials.There is still a lack of systematic scientific guidance on the relationship between the surface structure regulation and activity of carbon-based catalysts.In this review,some of electrochemical and computational fundamental concepts about ORR are concisely summarized.The effects of edge defect and nonmetallic doping of carbon materials on ORR behavior and mechanism have been reviewed,and activity origin identification and intermediate conversion mechanism have been discussed.The outlooks for future researches on metal-free ORR electrocatalysis are suggested.展开更多
The overall electrochemical performances of Ni-Zn batteries are still far from satisfactory, specifically for rate performance and cycling stability Herein, we demonstrated a high-performance flexible Ni//Zn battery w...The overall electrochemical performances of Ni-Zn batteries are still far from satisfactory, specifically for rate performance and cycling stability Herein, we demonstrated a high-performance flexible Ni//Zn battery with outstanding durability and high power density based on selfsupported NiCo_2 O_4 nanosheets as cathode and Zn nanosheets as anode. This Ni//Zn battery is able to deliver a remarkable capacity of183.1 mAh g^(-1) and a good cycling performance(82.7% capacity retention after 3500 cycles). More importantly, this battery achieves an admirable power density of 49.0 kW kg^(-1) and energy density of 303.8 Wh kg^(-1), substantially higher than most recently reported batteries. With such excellent electrochemical performance, this battery will have great potential as an ultrafast power source in practical application.展开更多
Ultrafast-charging energy storage devices are attractive for powering personal electronics and electric vehicles.Most ultrafast-charging devices are made of carbonaceous materials such as chemically converted graphene...Ultrafast-charging energy storage devices are attractive for powering personal electronics and electric vehicles.Most ultrafast-charging devices are made of carbonaceous materials such as chemically converted graphene and carbon nanotubes.Yet,their relatively low electrical conductivity may restrict their performance at ultrahigh charging rate.Here,we report the fabrication of a porous titanium nitride(TiN)paper as an alternative electrode material for ultrafast-charging devices.The TiN paper shows an excellent conductivity of 3.67×104 S m−1,which is considerably higher than most carbon-based electrodes.The paper-like structure also contains a combination of large pores between interconnected nanobelts and mesopores within the nanobelts.This unique electrode enables fast charging by simultaneously providing efficient ion diffusion and electron transport.The supercapacitors(SCs)made of TiN paper enable charging/discharging at an ultrahigh scan rate of 100 V s−1 in a wide voltage window of 1.5 V in Na2SO4 neutral electrolyte.It has an outstanding response time with a characteristic time constant of 4 ms.Significantly,the TiN paper-based SCs also show zero capacitance loss after 200,000 cycles,which is much better than the stability performance reported for other metal nitride SCs.Furthermore,the device shows great promise in scalability.The filtration method enables good control of the thickness and mass loading of TiN electrodes and devices.展开更多
Noncontact optical thermometers have attracted widespread attention,but existing problems such as single-mode and low-sensitivity thermometers still urgently need to be solved.Herein,a novel multiple-mode thermometer ...Noncontact optical thermometers have attracted widespread attention,but existing problems such as single-mode and low-sensitivity thermometers still urgently need to be solved.Herein,a novel multiple-mode thermometer was designed for the polymorphism LaSc_(3)(BO_(3))_(4):Eu^(2+/3+),Li^(+).X-ray diffraction(XRD)patterns revealed a slight transition betweenα-andβ-phases with the concentrations of the dopants,which is further proved by structure refinements and first-principles calculations.The coexistence of Eu^(2+)and Eu^(3+)in the phosphors and their relative percentages were confirmed by X-ray absorption near-edge structure(XANES)spectra.Benefiting from appropriate emissions from Eu^(2+)and Eu^(3+)without obvious energy transfer and their opposite changing trends with temperatures under 307 nm excitation,a triple-mode optical thermometer is obtained for this material within the temperature range of 150–450 K.The highest sensitivities of 27.65,14.05,and 7.68%·K^(−1)are achieved based on two fluorescence intensity ratio(FIR)modes of Eu^(2+)and Eu^(3+)(5d–4f/^(5)D_(0)–^(7)F_(2,4))and the fluorescence lifetime(FL)mode of Eu^(2+),respectively.To the best of our knowledge,the former is almost the highest in Eu^(2+)and Eu^(3+)co-doped thermometers.These results indicate that this material may be used as an excellent multiple-mode optical thermometer.展开更多
Lithium-ion batteries have emerged as the best portable energy storage device for the consumer electronics market. Recent progress in the development of lithium- ion batteries has been achieved by the use of selected ...Lithium-ion batteries have emerged as the best portable energy storage device for the consumer electronics market. Recent progress in the development of lithium- ion batteries has been achieved by the use of selected anode materials, which have driven improvements in performance in terms of capadty, cyclic stability, and rate capability. In this regard, research focusing on the design and electrochemical performance of full cell lithium-ion batteries, utilizing newly developed anode materials, has been widely reported, and great strides in development have been made. Nanostructured anode materials have contributed largely to the development of full cell lithium-ion batteries. With this in mind, we summarize the impact of nanostructured anode materials in the performance of coin cell full lithium-ion batteries. This review also discusses the challenges and prospects of research into full cell lithium-ion batteries.展开更多
Designing novel electrode materials with unique structures is of great significance for improving the performance of lithium ion batteries(LIBs).Herein,copper-doped Co_(1-x)Te@nitrogen-doped carbon hollow nanoboxes(Cu...Designing novel electrode materials with unique structures is of great significance for improving the performance of lithium ion batteries(LIBs).Herein,copper-doped Co_(1-x)Te@nitrogen-doped carbon hollow nanoboxes(Cu-Co_(1-x)Te@NC HNBs)have been fabricated by chemical etching of Cu Co-ZIF nanoboxes,followed by a successive high-temperature tellurization process.The as-synthesized Cu-Co_(1-x)Te@NC HNBs composite demonstrated faster ionic and electronic diffusion kinetics than the pristine Co Te@NC HNBs electrode.The existence of Co-vacancy promotes the reduction of Gibbs free energy change(ΔG_(H^(*)))and effectively improves the Li~+diffusion coefficient.XPS and theoretical calculations show that performance improvement is ascribed to the electronic interactions between Cu-Co_(1-x)Te and nitrogen-doped carbon(NC)that trigger the shift of the p-band towards facilitation of interfacial charge transfer,which in turn helps boost up the lithium storage property.Besides,the proposed Cu-doping-induced Co-vacancy strategy can also be extended to other conversion-type cobalt-based material(CoSe_(2))in addition to asobtained Cu-Co_(1-x)Se_(2)@NC HNBs anodes for long-life and high-capacity LIBs.More importantly,the fabricated LiCoO_(2)//Cu-Co_(1-x)Te@NC HNBs full cell exhibits a high energy density of 403 Wh kg^(-1)and a power density of 6000 W kg^(-1).We show that the energy/power density reported herein is higher than that of previously studied cobalt-based anodes,indicating the potential application of Cu-Co_(1-x)Te@NC HNBs as a superior electrode material for LIBs.展开更多
A porous hollow hybrid nanoarchitecture that consist of Co2 P/Co nanoparticles confined in nitrogendoped carbon(NC) and carbon nanotube(CNT) hollow nanocubes(denoted as H-Co2 P/Co-NC/CNT) has been rational designed as...A porous hollow hybrid nanoarchitecture that consist of Co2 P/Co nanoparticles confined in nitrogendoped carbon(NC) and carbon nanotube(CNT) hollow nanocubes(denoted as H-Co2 P/Co-NC/CNT) has been rational designed as anode for lithium ion batteries(LIBs) and electrocatalytic oxygen evolution reaction(OER).Such design involves simple synthetic process of using metal-organic frameworks(MOFs)as sacrificial precursor.The uniform cubic-shaped H-Co2 P/Co-NC/CNT hybrid is investigated with several intriguing advantages,including improved structural integrity,superior electronic conductivity,hollow architecture and large specific surface area and so on.The as-synthesized H-Co2 P/Co-NC/CNT displays excellent lithium storage behaviour in terms of long cycle life(> 500 cycles),remarkable rate performance(up to 5 A g^-1),high reversible capacity(601 mA hg^-1 at 0.2 A g^-1) and high pseudocapacitance behavior.Besides,it also delivers a superior catalytic property for OER with a small Ta fel slope of 45.3 mV dec^-1 and overpotential of 256 mV(at 10 mA cm^-2).The excellent performance can be attributed to the synergistic effect between Co2 P/Co and NC/CNT,leading to enhanced conductivity through high pseudocapacitance contribution.This present work demonstrates that MOF-derived H-Co2 P/Co-NC/CNT hybrid is a promising candidate for high-performance multifunctional energy systems.展开更多
Nanoscale metal-organic frameworks （NMOFs） have attracted increased attention in recent years for miniaturized and/or biological applications.However,the synthesis of ultrasmall NMOFs with good stability is a great ...Nanoscale metal-organic frameworks （NMOFs） have attracted increased attention in recent years for miniaturized and/or biological applications.However,the synthesis of ultrasmall NMOFs with good stability is a great challenge.In this study,sub-5-nm nano-HKUST-1 was prepared for the first time via a mild metalorganic gel route without surfactants or capping agents.Controlling the gelation process via anion-ligand self-assembly is the key to the formation of NMOFs.The Tyndall effect,zeta potential,and liquid adsorption indicated strong stability of the obtained nano-HKUST-1,even in water.Adsorption experiments were performed using different dyes （crystal violet and methylene blue） to demonstrate the size-dependent adsorption thermodynamics and kinetics of this famous MOF.The results of this study provide new insights regarding the synthesis of NMOFs and their efficient applications.展开更多
基金support from the National Natural Science Foundation of China(nos.21872041,21373091)the Science and Technology Project of Guangzhou city(no.201704030040)。
文摘Although scientists have conducted long-term and extensive studies on oxygen reduction reaction(ORR)catalyzed by metal-free carbon materials,they mainly have focused on the preparation and properties of various doped carbon materials.There is still a lack of systematic scientific guidance on the relationship between the surface structure regulation and activity of carbon-based catalysts.In this review,some of electrochemical and computational fundamental concepts about ORR are concisely summarized.The effects of edge defect and nonmetallic doping of carbon materials on ORR behavior and mechanism have been reviewed,and activity origin identification and intermediate conversion mechanism have been discussed.The outlooks for future researches on metal-free ORR electrocatalysis are suggested.
基金supported by the Guangdong Natural Science Funds for Distinguished Young Scholar (2014A030306048)National Natural Science Foundation of China (21403306)+3 种基金Tip-top Scientific and Technical Innovative Youth Talents of Guangdong Special Support Program (2015TQO1C205)Pearl River Nova Program of Guangzhou (201610010080)Open Fund of Jiangsu Key Laboratory of Materials and Technology for Energy Conversion (MTEC-2015M05)Training Program of Scientific and Technological Innovation for Undergraduates (pdjh2017a0003)
文摘The overall electrochemical performances of Ni-Zn batteries are still far from satisfactory, specifically for rate performance and cycling stability Herein, we demonstrated a high-performance flexible Ni//Zn battery with outstanding durability and high power density based on selfsupported NiCo_2 O_4 nanosheets as cathode and Zn nanosheets as anode. This Ni//Zn battery is able to deliver a remarkable capacity of183.1 mAh g^(-1) and a good cycling performance(82.7% capacity retention after 3500 cycles). More importantly, this battery achieves an admirable power density of 49.0 kW kg^(-1) and energy density of 303.8 Wh kg^(-1), substantially higher than most recently reported batteries. With such excellent electrochemical performance, this battery will have great potential as an ultrafast power source in practical application.
基金supported by Merced nAnomaterials Center for Energy and Sensing (MACES), a NASA funded MIRO center, under award NNX15AQ01supported by the US NSF MRI grant, MRI-1126845)
文摘Ultrafast-charging energy storage devices are attractive for powering personal electronics and electric vehicles.Most ultrafast-charging devices are made of carbonaceous materials such as chemically converted graphene and carbon nanotubes.Yet,their relatively low electrical conductivity may restrict their performance at ultrahigh charging rate.Here,we report the fabrication of a porous titanium nitride(TiN)paper as an alternative electrode material for ultrafast-charging devices.The TiN paper shows an excellent conductivity of 3.67×104 S m−1,which is considerably higher than most carbon-based electrodes.The paper-like structure also contains a combination of large pores between interconnected nanobelts and mesopores within the nanobelts.This unique electrode enables fast charging by simultaneously providing efficient ion diffusion and electron transport.The supercapacitors(SCs)made of TiN paper enable charging/discharging at an ultrahigh scan rate of 100 V s−1 in a wide voltage window of 1.5 V in Na2SO4 neutral electrolyte.It has an outstanding response time with a characteristic time constant of 4 ms.Significantly,the TiN paper-based SCs also show zero capacitance loss after 200,000 cycles,which is much better than the stability performance reported for other metal nitride SCs.Furthermore,the device shows great promise in scalability.The filtration method enables good control of the thickness and mass loading of TiN electrodes and devices.
基金financially supported by the National Natural Science Foundation of China(Nos.51972347 and 21771195).
文摘Noncontact optical thermometers have attracted widespread attention,but existing problems such as single-mode and low-sensitivity thermometers still urgently need to be solved.Herein,a novel multiple-mode thermometer was designed for the polymorphism LaSc_(3)(BO_(3))_(4):Eu^(2+/3+),Li^(+).X-ray diffraction(XRD)patterns revealed a slight transition betweenα-andβ-phases with the concentrations of the dopants,which is further proved by structure refinements and first-principles calculations.The coexistence of Eu^(2+)and Eu^(3+)in the phosphors and their relative percentages were confirmed by X-ray absorption near-edge structure(XANES)spectra.Benefiting from appropriate emissions from Eu^(2+)and Eu^(3+)without obvious energy transfer and their opposite changing trends with temperatures under 307 nm excitation,a triple-mode optical thermometer is obtained for this material within the temperature range of 150–450 K.The highest sensitivities of 27.65,14.05,and 7.68%·K^(−1)are achieved based on two fluorescence intensity ratio(FIR)modes of Eu^(2+)and Eu^(3+)(5d–4f/^(5)D_(0)–^(7)F_(2,4))and the fluorescence lifetime(FL)mode of Eu^(2+),respectively.To the best of our knowledge,the former is almost the highest in Eu^(2+)and Eu^(3+)co-doped thermometers.These results indicate that this material may be used as an excellent multiple-mode optical thermometer.
基金This work was supported by the National Natural Science Foundation of China （Nos. 21273290 and 21476271）, the Natural Science Foundation of Guangdong Province （Nos. S2013030013474 and 2014KTSCX004） and the Science and Technology Plan Project of Guangdong Province （Nos. 2014B101123002, 2014B050505001 and 2015B010118002）. We thank the Middle School Student Talent Plan.
文摘Lithium-ion batteries have emerged as the best portable energy storage device for the consumer electronics market. Recent progress in the development of lithium- ion batteries has been achieved by the use of selected anode materials, which have driven improvements in performance in terms of capadty, cyclic stability, and rate capability. In this regard, research focusing on the design and electrochemical performance of full cell lithium-ion batteries, utilizing newly developed anode materials, has been widely reported, and great strides in development have been made. Nanostructured anode materials have contributed largely to the development of full cell lithium-ion batteries. With this in mind, we summarize the impact of nanostructured anode materials in the performance of coin cell full lithium-ion batteries. This review also discusses the challenges and prospects of research into full cell lithium-ion batteries.
基金the Natural Science Foundation of Anhui Province Higher Education Institutions(No.KJ2021A0501)the Foundation of Scientific Research Project of Anhui Polytechnic University(No.Xjky2020090)+4 种基金the Anhui Laboratory of Functional Coordinated Complexes for Materials Chemistry and Application(Nos.LFCCMCA-01 and LFCCMCA-06)the Scientific Research Launch Project of Anhui Polytechnic University(No.2020YQQ057)the Innovation and Entrepreneurship Training Program for College Students in Anhui Province(No.S202110363265)the National Key Research and Development Program of China(2019YFA0705702)the National Natural Science Foundation of China(21902188)。
文摘Designing novel electrode materials with unique structures is of great significance for improving the performance of lithium ion batteries(LIBs).Herein,copper-doped Co_(1-x)Te@nitrogen-doped carbon hollow nanoboxes(Cu-Co_(1-x)Te@NC HNBs)have been fabricated by chemical etching of Cu Co-ZIF nanoboxes,followed by a successive high-temperature tellurization process.The as-synthesized Cu-Co_(1-x)Te@NC HNBs composite demonstrated faster ionic and electronic diffusion kinetics than the pristine Co Te@NC HNBs electrode.The existence of Co-vacancy promotes the reduction of Gibbs free energy change(ΔG_(H^(*)))and effectively improves the Li~+diffusion coefficient.XPS and theoretical calculations show that performance improvement is ascribed to the electronic interactions between Cu-Co_(1-x)Te and nitrogen-doped carbon(NC)that trigger the shift of the p-band towards facilitation of interfacial charge transfer,which in turn helps boost up the lithium storage property.Besides,the proposed Cu-doping-induced Co-vacancy strategy can also be extended to other conversion-type cobalt-based material(CoSe_(2))in addition to asobtained Cu-Co_(1-x)Se_(2)@NC HNBs anodes for long-life and high-capacity LIBs.More importantly,the fabricated LiCoO_(2)//Cu-Co_(1-x)Te@NC HNBs full cell exhibits a high energy density of 403 Wh kg^(-1)and a power density of 6000 W kg^(-1).We show that the energy/power density reported herein is higher than that of previously studied cobalt-based anodes,indicating the potential application of Cu-Co_(1-x)Te@NC HNBs as a superior electrode material for LIBs.
基金This work was supported by the National Natural Science Foundation of China(21875292and21706295)the National Key Research and Development Program of China(2016YFA0202604)+4 种基金Science Starting Foundation of Hunan University(531118010182)the Natural Science Foundation of Guangdong Province(2017A030313055)the Fundamental Research Funds for the Central Universities(17lgjc36)the Science and TechnologyPlan Project of Guangzhou,China(201804020025)China Postdoctoral Science Foundation(2018M640847)。
文摘A porous hollow hybrid nanoarchitecture that consist of Co2 P/Co nanoparticles confined in nitrogendoped carbon(NC) and carbon nanotube(CNT) hollow nanocubes(denoted as H-Co2 P/Co-NC/CNT) has been rational designed as anode for lithium ion batteries(LIBs) and electrocatalytic oxygen evolution reaction(OER).Such design involves simple synthetic process of using metal-organic frameworks(MOFs)as sacrificial precursor.The uniform cubic-shaped H-Co2 P/Co-NC/CNT hybrid is investigated with several intriguing advantages,including improved structural integrity,superior electronic conductivity,hollow architecture and large specific surface area and so on.The as-synthesized H-Co2 P/Co-NC/CNT displays excellent lithium storage behaviour in terms of long cycle life(> 500 cycles),remarkable rate performance(up to 5 A g^-1),high reversible capacity(601 mA hg^-1 at 0.2 A g^-1) and high pseudocapacitance behavior.Besides,it also delivers a superior catalytic property for OER with a small Ta fel slope of 45.3 mV dec^-1 and overpotential of 256 mV(at 10 mA cm^-2).The excellent performance can be attributed to the synergistic effect between Co2 P/Co and NC/CNT,leading to enhanced conductivity through high pseudocapacitance contribution.This present work demonstrates that MOF-derived H-Co2 P/Co-NC/CNT hybrid is a promising candidate for high-performance multifunctional energy systems.
基金This work was supported by the National Natural Science Foundation of China （No. 21571193）, Open Funds of the state key Laboratory of Rare Earth Resource Utilization （No. RERU2013012）, Science Foundation of Guangdong Province （No. 2015A030312007） and National Postdoctoral Program for Innovative Talents （No. BX201600195）.
文摘Nanoscale metal-organic frameworks （NMOFs） have attracted increased attention in recent years for miniaturized and/or biological applications.However,the synthesis of ultrasmall NMOFs with good stability is a great challenge.In this study,sub-5-nm nano-HKUST-1 was prepared for the first time via a mild metalorganic gel route without surfactants or capping agents.Controlling the gelation process via anion-ligand self-assembly is the key to the formation of NMOFs.The Tyndall effect,zeta potential,and liquid adsorption indicated strong stability of the obtained nano-HKUST-1,even in water.Adsorption experiments were performed using different dyes （crystal violet and methylene blue） to demonstrate the size-dependent adsorption thermodynamics and kinetics of this famous MOF.The results of this study provide new insights regarding the synthesis of NMOFs and their efficient applications.
