Metal-organic framework materials exhibit considerable potential as molecularly selective surfaceenhanced Raman spectroscopy(SERS)substrates because of their microporous structures,which enrich small molecules while e...Metal-organic framework materials exhibit considerable potential as molecularly selective surfaceenhanced Raman spectroscopy(SERS)substrates because of their microporous structures,which enrich small molecules while excluding larger ones.In this study,we develop a template-assisted chemical-etching strategy to prepare layered tuneable SERS substrates based on hierarchical porous zeolitic imidazolate framework-67(HP-ZIF-67)with a rhombic dodecahedral structure.The synergistic SERS enhancement mechanisms of HP-ZIF-67,which combine electromagnetic(EM)and chemical(CM)effects,were systematically studied through numerical simulations and experiments.Calculations revealed that under 633-nm laser excitation,the contributions of the EM and CM effects to the total SERS enhancement factor of HP-ZIF-67 were 60%and 40%,respectively.The hierarchical porous structure enhanced the fluid-flow flux over the microporous ZIF-67 because the increased pore radius reduced the viscous resistance and facilitated rapid molecular transport through the interconnected macro-meso-channels.Precise modulation of the CM and EM effects,combined with enhanced mass transfer,facilitated the development of HP-ZIF-67and HP-ZIF-67@Au as efficient SERS sensors.An investigation of the relationship between pore-size distribution and EM effects revealed the pivotal role of light confinement by whispering-gallery-mode microcavities in enhancing the SERS performance.The optimised HPZIF-67@Au composites functioned as flexible and highly sensitive in situ SERS sensors for gases and liquids,including volatile organic-compound gas and liquid-pesticide residues.This study introduces a novel design concept and provides a robust theoretical foundation for the future development of exhaled-breath point-of-care diagnostic devices and sweat-based wearable biomedical sensors.展开更多
With the continuous development of two-dimensional (2D) transition metal carbides and nitrides(collectively referred to as MXene).Nowadays,more than 70 MXene materials have been discovered,and the number is still incr...With the continuous development of two-dimensional (2D) transition metal carbides and nitrides(collectively referred to as MXene).Nowadays,more than 70 MXene materials have been discovered,and the number is still increasing.Among them,the V_(2)CT_(x) MXene has attracted considerable attentions due to its outstanding physical and chemical properties.In this review,we mainly discussed the emerging V_(2)CT_(x) MXene and its derivative systems in various energy storage devices.Firstly,an introduction of the V-based MXene and its derivatives along with their synthetic methodologies is provided,then we summarize their applications in specific energy storage devices,such as metal (Li,Na,K,Mg,Zn and Al) ion batteries,lithium-sulfur batteries,supercapacitors and metal-ion capacitors.Finally,the main challenges and future perspectives existing in V-based MXene and its derivatives are reasonably put forward.展开更多
Recently,CoCO_(3)has attracted enormous attention as anodes for lithium-ion batteries(LIBs),benefiting from its high theoretical capacity and simple synthesis.However,the modest electronic conductivity and structural ...Recently,CoCO_(3)has attracted enormous attention as anodes for lithium-ion batteries(LIBs),benefiting from its high theoretical capacity and simple synthesis.However,the modest electronic conductivity and structural instability over cycling hinder its wider applications.To well address the intrinsic issues,we explored a precipitantfree hydrothermal methodology for mass production of spindle-like CoCO_(3)/reduced graphene oxide(S-CoCO_(3)/rGO)toward advanced LIBs as a hybrid anode.The dimethylformamide plays a significant role of"two birds(i.e.,solvent and precipitant)with one stone"in the formation of the S-CoCO_(3)/rGO,greatly improving its practical applicability.The purposeful introduction of rGO nanosheets as a two-dimensional flexible conductive network enhances the conductivity and stability of the S-CoCO_(3).It is the structural and compositional merits for LIBs that endow the S-CoCO3/rGO with remarkable lithium-storage performance in terms of enhanced interfacial storage capacity,high-rate reversible capacities(803 mAh·g^(-1)at 2.0 A·g^(-1))and long-duration capacity retention of 82.1%over 2000 consecutive cycles at 2.0 A·g^(-1).More significantly,the simple yet efficient avenue here promises enormous commercial prospect of the S-CoCO_(3)/rGO in next-generation LIBs.展开更多
Potassium ion hybrid capacitors(PIHC)have promising applications in medium and large-scale energy storage systems due to their high energy/power density,abundant potassium resource and low cost.However,the slow kineti...Potassium ion hybrid capacitors(PIHC)have promising applications in medium and large-scale energy storage systems due to their high energy/power density,abundant potassium resource and low cost.However,the slow kinetics of battery-type anodes originating from the large-size K+results in a mismatch between the two electrodes,rendering the modest energy density of PIHC.Herein,we first develop an electrospinning strategy to successfully synthesize fibrous precursor by using the HNO_(3)pre-oxidized low-softening-point coal pitch as the low-cost raw material.With further carbonization or KOH activation,the two types of carbon nanofibers(CNF)are fabricated as anode and cathode materials,respectively,towards the dual-carbon PIHC devices.Thanks to its threedimensional interconnected porous conducting network and large layer spacing,the resulted CNF anode material is endowed with high reversible capacities,excellent rate and long cycle stability.Meanwhile,the activated CNF cathode with a large surface area of 2169 m^(2)·g^(-1)exhibits excellent capacitive performance.A PIHC constructed with the two fibrous electrodes delivers an energy density of110.0 Wh·kg^(-1)at 200.0 W kg^(-1),along with a capacitance retention of 83.5%after 10,000 cycles at 1.0 A·g^(-1).The contribution here provides a cost-efficiency avenue and platform for advanced dual-carbon PIHC.展开更多
The shuttling diffusion of polysulfides is a bottleneck that seriously limits the performance of Li-S batteries.Purposeful construction of sulfur cathodes with reliable trapping ability of polysulfides is the key to o...The shuttling diffusion of polysulfides is a bottleneck that seriously limits the performance of Li-S batteries.Purposeful construction of sulfur cathodes with reliable trapping ability of polysulfides is the key to overcome such limitation.Herein,a hierarchical porous architecture,i.e.,Co(OH)_(2)sheets bonded Ti_3C_(2)T_x MXene aerogel(Co(OH)_(2)/MXA),is constructed via a facile selfassembled approach and used as an efficient free-standing polysulfides reservoir.The interconnected three-dimensional(3D)porous network with void space and strong interfacial interaction not only enables high sulfur loading but facilitates fast ion and electron transport.Experimental and theoretical results confirm the hetero-framework exhibits outstanding immobilization and conversion ability for polysulfides due to its polar surface and bifunctional catalytic activities toward both formation and decomposition of Li2S.The optimized Co(OH)_(2)/MXA cathode delivers excellent rate capability(407 mAh·g^(-1)at 5C)with a sulfur loading of 2.7 mg·cm^(-2),and ultra-stable cycling performance as an extremely small capacity decay of~0.005%per cycle within 1700 cycles at 1C is achieved with a high sulfur loading of 6.7 mg·cm^(-2).More significantly,our design structural/componential methodology here promises the MXene-based aerogel electrodes for LiS batteries and beyond.展开更多
基金supported by the National Natural Science Foundation of China(Nos.62475128 and 12274055)Youth Innovation Team Program of Shandong Higher Education Institution(No.2024KJN016)+1 种基金Research Grants Council of Hong Kong through an ANR/RGC Joint Research Scheme grant(No.A-CityUl01/20)Centre for Functional Photonics of City University of Hong Kong,and Hong Kong Branch of National Precious Metals Material Engineering Research Center(ITC Fund)
文摘Metal-organic framework materials exhibit considerable potential as molecularly selective surfaceenhanced Raman spectroscopy(SERS)substrates because of their microporous structures,which enrich small molecules while excluding larger ones.In this study,we develop a template-assisted chemical-etching strategy to prepare layered tuneable SERS substrates based on hierarchical porous zeolitic imidazolate framework-67(HP-ZIF-67)with a rhombic dodecahedral structure.The synergistic SERS enhancement mechanisms of HP-ZIF-67,which combine electromagnetic(EM)and chemical(CM)effects,were systematically studied through numerical simulations and experiments.Calculations revealed that under 633-nm laser excitation,the contributions of the EM and CM effects to the total SERS enhancement factor of HP-ZIF-67 were 60%and 40%,respectively.The hierarchical porous structure enhanced the fluid-flow flux over the microporous ZIF-67 because the increased pore radius reduced the viscous resistance and facilitated rapid molecular transport through the interconnected macro-meso-channels.Precise modulation of the CM and EM effects,combined with enhanced mass transfer,facilitated the development of HP-ZIF-67and HP-ZIF-67@Au as efficient SERS sensors.An investigation of the relationship between pore-size distribution and EM effects revealed the pivotal role of light confinement by whispering-gallery-mode microcavities in enhancing the SERS performance.The optimised HPZIF-67@Au composites functioned as flexible and highly sensitive in situ SERS sensors for gases and liquids,including volatile organic-compound gas and liquid-pesticide residues.This study introduces a novel design concept and provides a robust theoretical foundation for the future development of exhaled-breath point-of-care diagnostic devices and sweat-based wearable biomedical sensors.
基金financially supported by the National Natural Science Foundation of China (Nos. 51772127, 51772131 and 52072151)Taishan Scholars (No. ts201712050)+2 种基金Jinan Independent Innovative Teamthe Natural Science Doctoral Foundation of Shandong Province (No. ZR2019BEM038)the Collaborative Innovation Center of Technology and Equipment for Biological Diagnosis and Therapy in Universities of Shandong。
文摘With the continuous development of two-dimensional (2D) transition metal carbides and nitrides(collectively referred to as MXene).Nowadays,more than 70 MXene materials have been discovered,and the number is still increasing.Among them,the V_(2)CT_(x) MXene has attracted considerable attentions due to its outstanding physical and chemical properties.In this review,we mainly discussed the emerging V_(2)CT_(x) MXene and its derivative systems in various energy storage devices.Firstly,an introduction of the V-based MXene and its derivatives along with their synthetic methodologies is provided,then we summarize their applications in specific energy storage devices,such as metal (Li,Na,K,Mg,Zn and Al) ion batteries,lithium-sulfur batteries,supercapacitors and metal-ion capacitors.Finally,the main challenges and future perspectives existing in V-based MXene and its derivatives are reasonably put forward.
基金financially supported by the National Natural Science Foundation of China(Nos.51772127 and 51772131)the Taishan Scholars(No.ts201712050)+3 种基金the Major Program of Shandong Province Natural Science Foundation(No.ZR2018ZB0317)the Natural Science Doctoral Foundation ofShandong Province(No.ZR2019BEM038)the Natural Science Doctoral Foundation of the University of Jinan(No.XBS1830)the Collaborative Innovation Center of Technology and Equipment for Biological Diagnosis and Therapy in Universities of Shandong。
文摘Recently,CoCO_(3)has attracted enormous attention as anodes for lithium-ion batteries(LIBs),benefiting from its high theoretical capacity and simple synthesis.However,the modest electronic conductivity and structural instability over cycling hinder its wider applications.To well address the intrinsic issues,we explored a precipitantfree hydrothermal methodology for mass production of spindle-like CoCO_(3)/reduced graphene oxide(S-CoCO_(3)/rGO)toward advanced LIBs as a hybrid anode.The dimethylformamide plays a significant role of"two birds(i.e.,solvent and precipitant)with one stone"in the formation of the S-CoCO_(3)/rGO,greatly improving its practical applicability.The purposeful introduction of rGO nanosheets as a two-dimensional flexible conductive network enhances the conductivity and stability of the S-CoCO_(3).It is the structural and compositional merits for LIBs that endow the S-CoCO3/rGO with remarkable lithium-storage performance in terms of enhanced interfacial storage capacity,high-rate reversible capacities(803 mAh·g^(-1)at 2.0 A·g^(-1))and long-duration capacity retention of 82.1%over 2000 consecutive cycles at 2.0 A·g^(-1).More significantly,the simple yet efficient avenue here promises enormous commercial prospect of the S-CoCO_(3)/rGO in next-generation LIBs.
基金financially supported by the National Natural Science Foundation of China(Nos.52072151 and 52171211)Taishan Scholars(No.ts201712050)+2 种基金Jinan Independent Innovative Team(No.2020GXRC015)the Natural Science Doctoral Foundation of Shandong Province(No.ZR2019BB057)the Major Program of Shandong Province Natural Science Foundation(No.ZR2021ZD05)。
文摘Potassium ion hybrid capacitors(PIHC)have promising applications in medium and large-scale energy storage systems due to their high energy/power density,abundant potassium resource and low cost.However,the slow kinetics of battery-type anodes originating from the large-size K+results in a mismatch between the two electrodes,rendering the modest energy density of PIHC.Herein,we first develop an electrospinning strategy to successfully synthesize fibrous precursor by using the HNO_(3)pre-oxidized low-softening-point coal pitch as the low-cost raw material.With further carbonization or KOH activation,the two types of carbon nanofibers(CNF)are fabricated as anode and cathode materials,respectively,towards the dual-carbon PIHC devices.Thanks to its threedimensional interconnected porous conducting network and large layer spacing,the resulted CNF anode material is endowed with high reversible capacities,excellent rate and long cycle stability.Meanwhile,the activated CNF cathode with a large surface area of 2169 m^(2)·g^(-1)exhibits excellent capacitive performance.A PIHC constructed with the two fibrous electrodes delivers an energy density of110.0 Wh·kg^(-1)at 200.0 W kg^(-1),along with a capacitance retention of 83.5%after 10,000 cycles at 1.0 A·g^(-1).The contribution here provides a cost-efficiency avenue and platform for advanced dual-carbon PIHC.
基金financially supported by the National Natural Science Foundation of China(Nos.52072151,52171211,52102253,52271218 and U22A20145)Jinan Independent Innovative Team(No.2020GXRC015)+1 种基金the Major Program of Shandong Province Natural Science Foundation(No.ZR2021ZD05)the Science and Technology Program of University of Jinan(Nos.XKY2119 and XKY2304)。
文摘The shuttling diffusion of polysulfides is a bottleneck that seriously limits the performance of Li-S batteries.Purposeful construction of sulfur cathodes with reliable trapping ability of polysulfides is the key to overcome such limitation.Herein,a hierarchical porous architecture,i.e.,Co(OH)_(2)sheets bonded Ti_3C_(2)T_x MXene aerogel(Co(OH)_(2)/MXA),is constructed via a facile selfassembled approach and used as an efficient free-standing polysulfides reservoir.The interconnected three-dimensional(3D)porous network with void space and strong interfacial interaction not only enables high sulfur loading but facilitates fast ion and electron transport.Experimental and theoretical results confirm the hetero-framework exhibits outstanding immobilization and conversion ability for polysulfides due to its polar surface and bifunctional catalytic activities toward both formation and decomposition of Li2S.The optimized Co(OH)_(2)/MXA cathode delivers excellent rate capability(407 mAh·g^(-1)at 5C)with a sulfur loading of 2.7 mg·cm^(-2),and ultra-stable cycling performance as an extremely small capacity decay of~0.005%per cycle within 1700 cycles at 1C is achieved with a high sulfur loading of 6.7 mg·cm^(-2).More significantly,our design structural/componential methodology here promises the MXene-based aerogel electrodes for LiS batteries and beyond.
