Efficient energy storage devices with suitable electrode materials,that integrate high power and high energy,are the crucial requisites of the renewable power source,which have unwrapped new possibilities in the susta...Efficient energy storage devices with suitable electrode materials,that integrate high power and high energy,are the crucial requisites of the renewable power source,which have unwrapped new possibilities in the sustainable development of energy and the environment.Herein,a facile collagen microstructure modulation strategy is proposed to construct a nitrogen/oxygen dual-doped hierarchically porous carbon fiber with ultrahigh specific surface area(2788 m^(2)g^(-1))and large pore volume(4.56 cm^(3)g^(-1))via local microfibrous breakage/disassembly of natural structured proteins.Combining operando spectroscopy and density functional theory unveil that the dual-heteroatom doping could effectively regulate the electronic structure of carbon atom framework with enhanced electric conductivity and electronegativity as well as decreased diffusion resistance in favor of rapid pseudocapacitive-dominated Li^(+)-storage(353 mAh g^(-1)at 10 A g^(-1)).Theoretical calculations reveal that the tailored micro-/mesoporous structures favor the rapid charge transfer and ion storage,synergistically realizing high capacity and superior rate performance for NPCF-H cathode(75.0 mAh g^(-1)at 30 A g^(-1)).The assembled device with NPCF-H as both anode and cathode achieves extremely high energy density(200 Wh kg^(-1))with maximum power density(42600 W kg^(-1))and ultralong lifespan(80%capacity retention over 10000 cycles).展开更多
Despite the significant progress in the fabrication of advanced electrode materials,complex control strategies and tedious processing are often involved for most targeted materials to tailor their compositions,morphol...Despite the significant progress in the fabrication of advanced electrode materials,complex control strategies and tedious processing are often involved for most targeted materials to tailor their compositions,morphologies,and chemistries.Inspired by the unique geometric structures of natural biomacromolecules together with their high affinities for metal species,we propose the use of skin collagen fibers for the template crafting of a novel multicore-shell Fe2N-carbon framework anode configuration,composed of hierarchical N-doped carbon nanofiber bundles firmly embedded with Fe2N nanoparticles(Fe2N@N-CFBs).In the resultant heterostructure,the Fe2N nanoparticles firmly confined inside the carbon shells are spatially isolated but electronically well connected by the long-range carbon nanofiber framework.This not only provides direct and continuous conductive pathways to facilitate electron/ion transport,but also helps cushion the volume expansion of the encapsulated Fe2N to preserve the electrode microstructure.Considering its unique structural characteristics,Fe2N@N-CFBs as an advanced anode material exhibits remarkable electrochemical performances for lithium-and potassium-ion batteries.Moreover,this bio-derived structural strategy can pave the way for novel low-cost and high-efficiency syntheses of metal-nitride/carbon nanofiber heterostructures for potential applications in energy-related fields and beyond.展开更多
Boosting the utilization efficiency of sulfur electrodes and suppressing the“shuttle effect”of intermediate polysulfides remain the critical challenge for high-performance lithium-sulfur batteries(LSBs).However,most...Boosting the utilization efficiency of sulfur electrodes and suppressing the“shuttle effect”of intermediate polysulfides remain the critical challenge for high-performance lithium-sulfur batteries(LSBs).However,most of reported sulfur electrodes are not competent to realize the fast conversion of polysulfides into insoluble lithium sulfides when applied with high sulfur loading,as well as to mitigate the more serious shuttle effect of polysulfides,especially when worked at an elevated temperature.Herein,we reported a unique structural engineering strategy of crafting a unique hierarchical multifunctional electrode architecture constructed by rooting MOF-derived CoS2/carbon nanoleaf arrays(CoS2-CNA)into a nitrogen-rich 3D conductive scaffold(CTNF@CoS2-CNA)for LSBs.An accelerated electrocatalytic effect and improved polysulfide redox kinetics arising from CoS2-CNA were investigated.Besides,the strong capillarity effect and chemisorption of CTNF@CoS2-CNA to polysulfides enable high loading and efficient utilization of sulfur,thus leading to high-performance LIBs performed not only at room temperature but also up to an elevated temperature(55°C).Even with the ultrahigh sulfur loading of 7.19 mg cm?2,the CTNF@CoS2-CNA/S cathode still exhibits high rate capacity at 55°C.展开更多
SeS_(2) has become a promising cathode material owing to its enhanced electrical conductivity over sulfur and higher theoretical specific capacity than selenium;however,the working Li-SeS_(2) batteries have to face th...SeS_(2) has become a promising cathode material owing to its enhanced electrical conductivity over sulfur and higher theoretical specific capacity than selenium;however,the working Li-SeS_(2) batteries have to face the practical challenges from the severe shuttling of soluble dual intermediates of polysulfide and polyselenide,especially in high-SeS_(2)-loading cathodes.Herein,a natural organic polymer,Nicandra physaloides pectin(NPP),is proposed to serve as an effective polysulfide/polyselenide captor to address the shuttling issues.Informed by theoretical calculations,NPP is competent to provide a Lewis base-based strong binding interaction with polysulfides/polyselenides via forming lithium bonds,and it can be homogeneously deposited onto a three-dimensional double-carbon conductive scaffold to finally constitute a polysulfide/polyselenide-immobilizing interlayer.Operando spectroscopy analysis validates the enhanced polysulfide/polyselenide trapping and high conversion efficiency on the constructed interlayer,hence bestowing the Li-SeS_(2) cells with ultrahigh rate capability(448 mAh g^(−1)at 10 A g^(−1)),durable cycling lifespan(≈0.037%capacity attenuation rate per cycle),and high areal capacity(>6.5 mAh cm^(−2))at high SeS_(2) loading of 15.4 mg cm^(−2).Importantly,pouch cells assembled with this interlayer exhibit excellent flexibility,decent rate capability with relatively low electrolyte-to-capacity ratio,and stable cycling life even under a low electrolyte condition,promising a low-cost,viable design protocol toward practical Li-SeS_(2) batteries.展开更多
Teaching quality is an important component which constitutes secondary and higher medical colleges,at the same time teaching quality monitoring system is the key content of teaching quality.In the current,teaching qua...Teaching quality is an important component which constitutes secondary and higher medical colleges,at the same time teaching quality monitoring system is the key content of teaching quality.In the current,teaching quality system of many Chinese schools is comparatively inadequate and the construction of quality assessment is comparatively backward and unsystematic.This research made further exploration into the above question with effective scheme found question,among which finding effective scheme is the main method to guarantee the improvement and soundness of teaching quality monitoring system.展开更多
The undesirable shuttle effect and sluggish redox kinetics of polysulfides seriously result in low sulfur utilization and poor capacity retention.Here,an integrated strategy is proposed by rational designing multifunc...The undesirable shuttle effect and sluggish redox kinetics of polysulfides seriously result in low sulfur utilization and poor capacity retention.Here,an integrated strategy is proposed by rational designing multifunctional architecture to manipulate the redox kinetics of polysulfides,specifically,by employing iron atoms(Fe-As)and iron-species nanoparticles(Fe-NPs)co-embedded nitrogen-doped carbon nanotube(Fe-NCNT)as catalyst and host for sulfur.The synergistic cooperation of Fe-As and Fe-NPs provides efficient active sites to facilitate the diffusion,strengthen the affinities,and promote the conversion reactions for polysulfides.Furthermore,the NCNT not only offers practical Li+transport pathways but also immobilize the polysulfides effectively.Benefiting from these merits,the Fe-NCNT/S electrodes exhibit high initial specific capacity of 1502.6 mAh/g at 0.1 C,outstanding rate performance(830 mAh/g at 2 C),and good cycling performance(597.8 mAh/g after 500 cycles with an ultralow capacity fading rate of 0.069%per cycle).This work features the distinct interaction of iron atom-nanoparticles on facilitating immobilization-diffusion-transformation process of polysulfides,and it also expected to pave the way for the application in practical Li-S batteries.展开更多
基金financial support from the National Natural Science Foundation of China(21878192 and 51904193)the Fundamental Research Funds for the Central Universities(YJ2021141)the Science and Technology Cooperation Special Fund of Sichuan University and Zigong City(2021CDZG-14)
文摘Efficient energy storage devices with suitable electrode materials,that integrate high power and high energy,are the crucial requisites of the renewable power source,which have unwrapped new possibilities in the sustainable development of energy and the environment.Herein,a facile collagen microstructure modulation strategy is proposed to construct a nitrogen/oxygen dual-doped hierarchically porous carbon fiber with ultrahigh specific surface area(2788 m^(2)g^(-1))and large pore volume(4.56 cm^(3)g^(-1))via local microfibrous breakage/disassembly of natural structured proteins.Combining operando spectroscopy and density functional theory unveil that the dual-heteroatom doping could effectively regulate the electronic structure of carbon atom framework with enhanced electric conductivity and electronegativity as well as decreased diffusion resistance in favor of rapid pseudocapacitive-dominated Li^(+)-storage(353 mAh g^(-1)at 10 A g^(-1)).Theoretical calculations reveal that the tailored micro-/mesoporous structures favor the rapid charge transfer and ion storage,synergistically realizing high capacity and superior rate performance for NPCF-H cathode(75.0 mAh g^(-1)at 30 A g^(-1)).The assembled device with NPCF-H as both anode and cathode achieves extremely high energy density(200 Wh kg^(-1))with maximum power density(42600 W kg^(-1))and ultralong lifespan(80%capacity retention over 10000 cycles).
基金financial support from the National Natural Science Foundation of China(21878192,51502180)the Fundamental Research Funds for the Central Universities(2016SCU04A18)+1 种基金the 1000 Talents Program of Sichuan Province,the Sichuan Province Science and Technology Support Program(2014GZ0093)the Australian Research Council(DP160102627).
文摘Despite the significant progress in the fabrication of advanced electrode materials,complex control strategies and tedious processing are often involved for most targeted materials to tailor their compositions,morphologies,and chemistries.Inspired by the unique geometric structures of natural biomacromolecules together with their high affinities for metal species,we propose the use of skin collagen fibers for the template crafting of a novel multicore-shell Fe2N-carbon framework anode configuration,composed of hierarchical N-doped carbon nanofiber bundles firmly embedded with Fe2N nanoparticles(Fe2N@N-CFBs).In the resultant heterostructure,the Fe2N nanoparticles firmly confined inside the carbon shells are spatially isolated but electronically well connected by the long-range carbon nanofiber framework.This not only provides direct and continuous conductive pathways to facilitate electron/ion transport,but also helps cushion the volume expansion of the encapsulated Fe2N to preserve the electrode microstructure.Considering its unique structural characteristics,Fe2N@N-CFBs as an advanced anode material exhibits remarkable electrochemical performances for lithium-and potassium-ion batteries.Moreover,this bio-derived structural strategy can pave the way for novel low-cost and high-efficiency syntheses of metal-nitride/carbon nanofiber heterostructures for potential applications in energy-related fields and beyond.
基金financial support from the National Key Research and Development Program of China(2018YFB0104201).
文摘Boosting the utilization efficiency of sulfur electrodes and suppressing the“shuttle effect”of intermediate polysulfides remain the critical challenge for high-performance lithium-sulfur batteries(LSBs).However,most of reported sulfur electrodes are not competent to realize the fast conversion of polysulfides into insoluble lithium sulfides when applied with high sulfur loading,as well as to mitigate the more serious shuttle effect of polysulfides,especially when worked at an elevated temperature.Herein,we reported a unique structural engineering strategy of crafting a unique hierarchical multifunctional electrode architecture constructed by rooting MOF-derived CoS2/carbon nanoleaf arrays(CoS2-CNA)into a nitrogen-rich 3D conductive scaffold(CTNF@CoS2-CNA)for LSBs.An accelerated electrocatalytic effect and improved polysulfide redox kinetics arising from CoS2-CNA were investigated.Besides,the strong capillarity effect and chemisorption of CTNF@CoS2-CNA to polysulfides enable high loading and efficient utilization of sulfur,thus leading to high-performance LIBs performed not only at room temperature but also up to an elevated temperature(55°C).Even with the ultrahigh sulfur loading of 7.19 mg cm?2,the CTNF@CoS2-CNA/S cathode still exhibits high rate capacity at 55°C.
基金by the National Key Research&Development Program of China(2018YFB0104200)the National Natural Science Foundation of China(201878192 and 51904193).
文摘SeS_(2) has become a promising cathode material owing to its enhanced electrical conductivity over sulfur and higher theoretical specific capacity than selenium;however,the working Li-SeS_(2) batteries have to face the practical challenges from the severe shuttling of soluble dual intermediates of polysulfide and polyselenide,especially in high-SeS_(2)-loading cathodes.Herein,a natural organic polymer,Nicandra physaloides pectin(NPP),is proposed to serve as an effective polysulfide/polyselenide captor to address the shuttling issues.Informed by theoretical calculations,NPP is competent to provide a Lewis base-based strong binding interaction with polysulfides/polyselenides via forming lithium bonds,and it can be homogeneously deposited onto a three-dimensional double-carbon conductive scaffold to finally constitute a polysulfide/polyselenide-immobilizing interlayer.Operando spectroscopy analysis validates the enhanced polysulfide/polyselenide trapping and high conversion efficiency on the constructed interlayer,hence bestowing the Li-SeS_(2) cells with ultrahigh rate capability(448 mAh g^(−1)at 10 A g^(−1)),durable cycling lifespan(≈0.037%capacity attenuation rate per cycle),and high areal capacity(>6.5 mAh cm^(−2))at high SeS_(2) loading of 15.4 mg cm^(−2).Importantly,pouch cells assembled with this interlayer exhibit excellent flexibility,decent rate capability with relatively low electrolyte-to-capacity ratio,and stable cycling life even under a low electrolyte condition,promising a low-cost,viable design protocol toward practical Li-SeS_(2) batteries.
文摘Teaching quality is an important component which constitutes secondary and higher medical colleges,at the same time teaching quality monitoring system is the key content of teaching quality.In the current,teaching quality system of many Chinese schools is comparatively inadequate and the construction of quality assessment is comparatively backward and unsystematic.This research made further exploration into the above question with effective scheme found question,among which finding effective scheme is the main method to guarantee the improvement and soundness of teaching quality monitoring system.
基金supported by the Natural Science Foundation of China(Nos.22125902,U2032202,21975243 and 21825302)the National Program for Support of Topnotch Young Professionals,the Fundamental Research Funds for the Central Universities(No.WK2030020032)+1 种基金the DNL cooperation Fund,CAS(No.DNL202020)the Anhui Science Fund for Distinguished Young Scholars(No.2208085J15).
文摘The undesirable shuttle effect and sluggish redox kinetics of polysulfides seriously result in low sulfur utilization and poor capacity retention.Here,an integrated strategy is proposed by rational designing multifunctional architecture to manipulate the redox kinetics of polysulfides,specifically,by employing iron atoms(Fe-As)and iron-species nanoparticles(Fe-NPs)co-embedded nitrogen-doped carbon nanotube(Fe-NCNT)as catalyst and host for sulfur.The synergistic cooperation of Fe-As and Fe-NPs provides efficient active sites to facilitate the diffusion,strengthen the affinities,and promote the conversion reactions for polysulfides.Furthermore,the NCNT not only offers practical Li+transport pathways but also immobilize the polysulfides effectively.Benefiting from these merits,the Fe-NCNT/S electrodes exhibit high initial specific capacity of 1502.6 mAh/g at 0.1 C,outstanding rate performance(830 mAh/g at 2 C),and good cycling performance(597.8 mAh/g after 500 cycles with an ultralow capacity fading rate of 0.069%per cycle).This work features the distinct interaction of iron atom-nanoparticles on facilitating immobilization-diffusion-transformation process of polysulfides,and it also expected to pave the way for the application in practical Li-S batteries.
