The microstructure design for thermal conduction pathways in polymeric electrical encapsulation materials is essential to meet the stringent requirements for efficient thermal management and thermal runaway safety in ...The microstructure design for thermal conduction pathways in polymeric electrical encapsulation materials is essential to meet the stringent requirements for efficient thermal management and thermal runaway safety in modern electronic devices.Hence,a composite with three-dimensional network(Ho/U-BNNS/WPU)is developed by simultaneously incorporating magnetically modified boron nitride nanosheets(M@BNNS)and non-magnetic organo-grafted BNNS(U-BNNS)into waterborne polyurethane(WPU)to synchronous molding under a horizontal magnetic field.The results indicate that the continuous in-plane pathways formed by M@BNNS aligned along the magnetic field direction,combined with the bridging structure established by U-BNNS,enable Ho/U-BNNS/WPU to exhibit exceptional in-plane(λ//)and through-plane thermal conductivities(λ_(⊥)).In particular,with the addition of 30 wt%M@BNNS and 5 wt%U-BNNS,theλ//andλ_(⊥)of composites reach 11.47 and 2.88 W m^(-1) K^(-1),respectively,which representing a 194.2%improvement inλ_(⊥)compared to the composites with a single orientation of M@BNNS.Meanwhile,Ho/U-BNNS/WPU exhibits distinguished thermal management capabilities as thermal interface materials for LED and chips.The composites also demonstrate excellent flame retardancy,with a peak heat release and total heat release reduced by 58.9%and 36.9%,respectively,compared to WPU.Thus,this work offers new insights into the thermally conductive structural design and efficient flame-retardant systems of polymer composites,presenting broad application potential in electronic packaging fields.展开更多
The implementation of ultrahigh-Ni cathodes in high-energy lithium-ion batteries(LIBs)is constrained by significant structural and interfacial degradation during cycling.In this study,doping-induced surface restructur...The implementation of ultrahigh-Ni cathodes in high-energy lithium-ion batteries(LIBs)is constrained by significant structural and interfacial degradation during cycling.In this study,doping-induced surface restructuring in ultrahigh-nickel cathode materials is rapidly facilitated through an ultrafast Joule heating method.Density functional theory(DFT)calculations,synchrotron X-ray absorption spectroscopy(XAS),and single-particle force test confirmed the establishment of a stable crystal framework and lattice oxygen,which mitigated H2-H3 phase transitions and improved structural reversibility.Additionally,the Sc doping process exhibits a pinning effect on the grain boundaries,as shown by scanning transmission electron microscopy(STEM),enhancing Li~+diffusion kinetics and decreasing mechanical strain during cycling.The in situ development of a cation-mixing layer at grain boundaries also creates a robust cathode/electrolyte interphase,effectively reducing interfacial parasitic reactions and transition metal dissolution,as validated by STEM and time-of-flight secondary ion mass spectrometry(TOF-SIMS).These synergistic modifications reduce particle cracking and surface/interface degradation,leading to enhanced rate capability,structural integrity,and thermal stability.Consequently,the optimized Sc-modified ultrahigh-Ni cathode(Sc-1)exhibits 93.99%capacity retention after 100 cycles at 1 C(25℃)and87.06%capacity retention after 100 cycles at 1 C(50℃),indicating excellent cycling and thermal stability.By presenting a one-step multifunctional modification approach,this research delivers an extensive analysis of the mechanisms governing the structure,microstructure,and interface properties of nickel-rich layered cathode materials(NCMs).These results underscore the potential of ultrahigh-Ni cathodes as viable candidates for advanced lithium-ion batteries(LIBs)in next-generation electric vehicles(EVs).展开更多
MnCO_(3)represents a potentially high-capacity and low-cost anode candidate to replace graphite for enhancing energy density of commercial lithium-ion batteries,but it suffers from poor electrical conductivity and ser...MnCO_(3)represents a potentially high-capacity and low-cost anode candidate to replace graphite for enhancing energy density of commercial lithium-ion batteries,but it suffers from poor electrical conductivity and serious volumetric change,largely hindering its practical applications.展开更多
Lithium metal anode is one of the ideal anode materials for the next generation of high-energy-density battery systems.Unfortunately,the uneven nucleation of Li leads to dendrite growth and volume changes during cycli...Lithium metal anode is one of the ideal anode materials for the next generation of high-energy-density battery systems.Unfortunately,the uneven nucleation of Li leads to dendrite growth and volume changes during cycling,resulting in poor electrochemical performance and potential safety hazards,which hinder its practical application.In this work,a low-cost chicken-bonederived carbon material(CBC)with a biomimetic structure was designed and synthesized using a simple one-step carbonization method.Combining theoretical calculations and experimental results,the self-doped N and S heteroatoms in CBC are demonstrated to effectively reduce the binding energy with Li atoms and lower the nucleation overpotential.After uniform nucleation,the Li metal grows in a spherical shape without dendrites,which is related to the reduction of the local current density inside the biomimetic crosslinking structure of CBC.Benefiting from this favorable Li growth behavior,the Li@CBC electrode achieves ultra-low nucleation overpotential(15.5 mV at 0.1 mA cm^(−2))and superdense lithium deposition(zero volume expansion rate at a capacity of 2 mAh cm^(−2))without introducing additional lithiophilic sites.The CBC retains a high Coulombic efficiency of over 98%in 479 cycles(1 mA cm^(−2)and 1 mAh cm^(−2))when applied in a half-cell with Li,and shows an excellent rate and cycling performance when applied in a full cell with LiFePO4 as the cathode.展开更多
Aqueous zinc-ion batteries(AZIBs)are pivotal for achieving net-zero goals,yet their commercialization is impeded by zinc dendrites,parasitic reactions,and interfacial instability.Current debates persist on the interpl...Aqueous zinc-ion batteries(AZIBs)are pivotal for achieving net-zero goals,yet their commercialization is impeded by zinc dendrites,parasitic reactions,and interfacial instability.Current debates persist on the interplay between zincophilic-hydrophilic and zincophobic-hydrophobic interactions at the anode-electrolyte interface.Herein,a conceptual framework that decouples these competing effects was proposed,enabling the rational design of a dual-layer architecture with an inner zincophilic layer for Zn^(2+)flux homogenization and an outer hydrophobic layer for water shielding.Through in situ and ex situ analyses,the synergistic mechanism was elucidated.During the cycling process,the zincophilic interface guides uniform Zn deposition,while the hydrophobic coating suppresses H_(2)O-induced side reactions.This dual modification achieves a Zn||Cu cell with an unprecedented 99.89%Coulombic efficiency and 975-cycle stability.This work resolves the long-standing controversy over interfacial affinity design,offering a scalable and industrially viable strategy to enhance AZIBs’durability without sacrificing energy density.展开更多
The burgeoning growth in electric vehicles and portable energy storage systems necessitates advances in the energy density and cost-effectiveness of lithium-ion batteries(LIBs),areas where lithium-rich manganese-based...The burgeoning growth in electric vehicles and portable energy storage systems necessitates advances in the energy density and cost-effectiveness of lithium-ion batteries(LIBs),areas where lithium-rich manganese-based oxide(LLO)materials naturally stand out.Despite their inherent advantages,these materials encounter significant practical hurdles,including low initial Coulombic efficiency(ICE),diminished cycle/rate performance,and voltage fading during cycling,hindering their widespread adoption.In response,we introduce an ionic-electronic dual-conductive(IEDC)surface control strategy that integrates an electronically conductive graphene framework with an ionically conductive heteroepitaxial spinel Li_(4)Mn_(5)O_(12)layer.Prolonged electrochemical and structural analyses demonstrate that this IEDC heterostructure effectively minimizes polarization,mitigates structural distortion,and enhances electronic/ionic diffusion.Density functional theory calculations highlight an extensive Li^(+)percolation network and lower Li^(+)migration energies at the layered-spinel interface.The designed LLO cathode with IEDC interface engineering(LMOSG)exhibits improved ICE(82.9%at 0.1 C),elevated initial discharge capacity(296.7 mAh g^(-1)at 0.1 C),exceptional rate capability(176.5 mAh g^(-1)at 5 C),and outstanding cycle stability(73.7%retention at 5 C after 500 cycles).These findings and the novel dual-conductive surface architecture design offer promising directions for advancing highperformance electrode materials.展开更多
Silicon‐based anode materials have garnered considerable attention in lithium‐ion batteries(LIBs)due to their exceptionally high theoretical capacity and energy density.However,intrinsic challenges,such as significa...Silicon‐based anode materials have garnered considerable attention in lithium‐ion batteries(LIBs)due to their exceptionally high theoretical capacity and energy density.However,intrinsic challenges,such as significant volumetric expansion and the consequent degradation in cycling stability,severely hinder their practical application.As a result,development of silicon anodes that can effectively mitigate volumetric expansions,enhance cycling durability,and improve rate performance has emerged as a critical research focus.However,due to neglect of“size effects”,the modification strategy of silicon‐based electrodes lacks systematic,scientific,and comprehensive guidance.Herein,this review starts from the“size effect”of silicon‐based materials,and reveals in depth the different failure mechanisms of nano‐silicon(Si NPs)and micro‐silicon(μSi).Furthermore,this review provides targeted classification of modification strategies for Si NPs andμSi,and reviews comprehensively,in detail,and in depth the latest research progress on silicon‐based materials.In addition,the review also comprehensively summarizes the cutting‐edge dynamics of matching silicon‐based electrodes with solid electrolytes to construct high‐energy LIBs.It is hoped that this review can provide comprehensive and systematic scientific guidance for modification strategies of silicon‐based electrodes,which is of great significance for promoting the industrialization process of silicon‐based electrodes in high‐energy LIBs.展开更多
The great interest of Fe-N/C based Zn-air batteries and fuel cells intrigues large numbers of studies on modulating the pore structure for fast mass transport and the electronic structure of atomic Fe centers for enha...The great interest of Fe-N/C based Zn-air batteries and fuel cells intrigues large numbers of studies on modulating the pore structure for fast mass transport and the electronic structure of atomic Fe centers for enhancing intrinsic activity for oxygen reduction reaction(ORR).A Zn-assisted strategy herein is developed to synthesize a honeycomb-like micro-nanoscale porous Fe-N/C catalyst with atomic FeN_(3)Cl active sites.Specifically,Zn-guided synthesis of honeycomb-like porous carbon supported ZnO,ZnO-templated assembly of hemin modified ZIF-8 on honeycomb-like carbon and Zn/ZnO-assisted pyrolysis of the ZIF-8 precursor are involved.The synthetic mechanism is revealed by in-situ transmission electron microscopy imaging and in-situ X-ray diffraction analysis.Density functional theory calculations demonstrate FeN_(3)Cl can prominently lower the ORR energy barrier on the Fe centers,greatly facilitating catalytic kinetics.Hence,high ORR performance,including half-wave potentials of 0.81 V in acidic conditions and 0.91 V under alkaline media,is achieved.Besides,Zn-air batteries and H_(2)-O_(2)fuel cells base on the resulting catalyst are investigated,also exhibiting excellent battery/cell performances.This study provides a novel strategy for the preparation of honeycomb-like micro-nanoscale porous single-atom catalysts as well as a significant new insight on the catalytic mechanisms,helping to advance in energy devices.展开更多
The rapid expansion of the automotive sector has significantly increased the demand for highperformance lithium-ion batteries,positioning Ni-rich layered cathodes as a promising solution due to their high energy densi...The rapid expansion of the automotive sector has significantly increased the demand for highperformance lithium-ion batteries,positioning Ni-rich layered cathodes as a promising solution due to their high energy density and cost-efficiency.However,these cathodes face critical challenges,including thermal instability and structural degradation at an elevated temperature,which hinder their practical application.This study introduces an advanced surface reconstruction strategy combining a LiScF_(4)coating,Sc/F surface co-doping,and a cation-mixing layer to address these issues.The LiScF_(4)coating serves as a durable protective barrier,reducing electrolyte decomposition,minimizing transition metal dissolution,and enhancing lithium-ion transport.Sc/F surface co-doping stabilizes lattice oxygen by increasing the energy barrier for oxygen vacancy formation and minimizing oxygen release,thereby suppressing phase transitions and interfacial side reactions.Additionally,the cation-mixing layer improves interfacial stability by alleviating lattice strain and supporting reversible cation migration,ensuring prolonged durability during cycling and under high-temperature conditions.These integrated modifications work synergistically to mitigate various degradation mechanisms,significantly improving the thermal stability,structural integrity,and electrochemical performance of Ni-rich cathodes.This approach offers a viable pathway for incorporating Ni-rich cathodes into advanced lithium-ion batteries,making them well-suited for applications requiring high thermal stability.Moreover,this research provides valuable guidance for the development of a multi-component modification strategy,paving the way for future innovations in energy storage materials and advancing high-performance battery technology.展开更多
Lithium metal is a compelling choice as an anode material for high-energy-density batteries,attributed to its elevated theoretical specific energy and low redox potential.Nevertheless,challenges arise due to its susce...Lithium metal is a compelling choice as an anode material for high-energy-density batteries,attributed to its elevated theoretical specific energy and low redox potential.Nevertheless,challenges arise due to its susceptibility to high-volume changes and the tendency for dendritic development during cycling,leading to restricted cycle life and diminished Coulombic efficiency(CE).Here,we innovatively engineered a kind of porous biocarbon to serve as the framework for a lithium metal anode,which boasts a heightened specific surface area and uniformly dispersed ZnO active sites,directly derived from metasequoia cambium.The porous structure efficiently mitigates local current density and alleviates the volume expansion of lithium.Also,incorporating the ZnO lithiophilic site notably reduces the nucleation overpotential to a mere 16 mV,facilitating the deposition of lithium in a compact form.As a result,this innovative material ensures an impressive CE of 98.5%for lithium plating/stripping over 500 cycles,a remarkable cycle life exceeding 1200 h in a Li symmetrical cell,and more than 82%capacity retention ratio after an astonishing 690 cycles in full cells.In all,such a rationally designed Li composite anode effectively mitigates volume change,enhances lithophilicity,and reduces local current density,thereby inhibiting dendrite formation.The preparation of a highperformance lithium anode frame proves the feasibility of using biocarbon in a lithium anode frame.展开更多
基金support from the National Natural Science Foundation of China(22268025,52473083,and 22475176)Key Research and Development Program of Yunnan Province(202403AP140036)+2 种基金Natural Science Basic Research Program of Shaanxi(2024JC-TBZC-04)Applied Basic Research Program of Yunnan Province(202201AT070115 and 202201BE070001-031)supported by the Innovation Capability Support Program of Shaanxi(2024RS-CXTD-57).
文摘The microstructure design for thermal conduction pathways in polymeric electrical encapsulation materials is essential to meet the stringent requirements for efficient thermal management and thermal runaway safety in modern electronic devices.Hence,a composite with three-dimensional network(Ho/U-BNNS/WPU)is developed by simultaneously incorporating magnetically modified boron nitride nanosheets(M@BNNS)and non-magnetic organo-grafted BNNS(U-BNNS)into waterborne polyurethane(WPU)to synchronous molding under a horizontal magnetic field.The results indicate that the continuous in-plane pathways formed by M@BNNS aligned along the magnetic field direction,combined with the bridging structure established by U-BNNS,enable Ho/U-BNNS/WPU to exhibit exceptional in-plane(λ//)and through-plane thermal conductivities(λ_(⊥)).In particular,with the addition of 30 wt%M@BNNS and 5 wt%U-BNNS,theλ//andλ_(⊥)of composites reach 11.47 and 2.88 W m^(-1) K^(-1),respectively,which representing a 194.2%improvement inλ_(⊥)compared to the composites with a single orientation of M@BNNS.Meanwhile,Ho/U-BNNS/WPU exhibits distinguished thermal management capabilities as thermal interface materials for LED and chips.The composites also demonstrate excellent flame retardancy,with a peak heat release and total heat release reduced by 58.9%and 36.9%,respectively,compared to WPU.Thus,this work offers new insights into the thermally conductive structural design and efficient flame-retardant systems of polymer composites,presenting broad application potential in electronic packaging fields.
基金supported by the National Key R&D Program of China(2022YFB3803501)the National Natural Science Foundation of China(22179008,22209156)+5 种基金support from the Beijing Nova Program(20230484241)support from the China Postdoctoral Science Foundation(2024M754084)the Postdoctoral Fellowship Program of CPSF(GZB20230931)support from beamline BL08U1A of Shanghai Synchrotron Radiation Facility(2024-SSRF-PT-506950)beamline 1W1B of the Beijing Synchrotron Radiation Facility(2021-BEPC-PT-006276)support from Initial Energy Science&Technology Co.,Ltd(IEST)。
文摘The implementation of ultrahigh-Ni cathodes in high-energy lithium-ion batteries(LIBs)is constrained by significant structural and interfacial degradation during cycling.In this study,doping-induced surface restructuring in ultrahigh-nickel cathode materials is rapidly facilitated through an ultrafast Joule heating method.Density functional theory(DFT)calculations,synchrotron X-ray absorption spectroscopy(XAS),and single-particle force test confirmed the establishment of a stable crystal framework and lattice oxygen,which mitigated H2-H3 phase transitions and improved structural reversibility.Additionally,the Sc doping process exhibits a pinning effect on the grain boundaries,as shown by scanning transmission electron microscopy(STEM),enhancing Li~+diffusion kinetics and decreasing mechanical strain during cycling.The in situ development of a cation-mixing layer at grain boundaries also creates a robust cathode/electrolyte interphase,effectively reducing interfacial parasitic reactions and transition metal dissolution,as validated by STEM and time-of-flight secondary ion mass spectrometry(TOF-SIMS).These synergistic modifications reduce particle cracking and surface/interface degradation,leading to enhanced rate capability,structural integrity,and thermal stability.Consequently,the optimized Sc-modified ultrahigh-Ni cathode(Sc-1)exhibits 93.99%capacity retention after 100 cycles at 1 C(25℃)and87.06%capacity retention after 100 cycles at 1 C(50℃),indicating excellent cycling and thermal stability.By presenting a one-step multifunctional modification approach,this research delivers an extensive analysis of the mechanisms governing the structure,microstructure,and interface properties of nickel-rich layered cathode materials(NCMs).These results underscore the potential of ultrahigh-Ni cathodes as viable candidates for advanced lithium-ion batteries(LIBs)in next-generation electric vehicles(EVs).
基金supported by the National Natural Science Foundation of China(Nos.52102088 and 22075026)support from Teli Fellowship,Beijing Institute of Technology,and facility support from Analysis&Testing Center,and Experimental Center of Materials Sciences&Engineering at Beijing Institute of Technology.
文摘MnCO_(3)represents a potentially high-capacity and low-cost anode candidate to replace graphite for enhancing energy density of commercial lithium-ion batteries,but it suffers from poor electrical conductivity and serious volumetric change,largely hindering its practical applications.
基金National Natural Science Foundation of China,Grant/Award Numbers:22179005,92372207。
文摘Lithium metal anode is one of the ideal anode materials for the next generation of high-energy-density battery systems.Unfortunately,the uneven nucleation of Li leads to dendrite growth and volume changes during cycling,resulting in poor electrochemical performance and potential safety hazards,which hinder its practical application.In this work,a low-cost chicken-bonederived carbon material(CBC)with a biomimetic structure was designed and synthesized using a simple one-step carbonization method.Combining theoretical calculations and experimental results,the self-doped N and S heteroatoms in CBC are demonstrated to effectively reduce the binding energy with Li atoms and lower the nucleation overpotential.After uniform nucleation,the Li metal grows in a spherical shape without dendrites,which is related to the reduction of the local current density inside the biomimetic crosslinking structure of CBC.Benefiting from this favorable Li growth behavior,the Li@CBC electrode achieves ultra-low nucleation overpotential(15.5 mV at 0.1 mA cm^(−2))and superdense lithium deposition(zero volume expansion rate at a capacity of 2 mAh cm^(−2))without introducing additional lithiophilic sites.The CBC retains a high Coulombic efficiency of over 98%in 479 cycles(1 mA cm^(−2)and 1 mAh cm^(−2))when applied in a half-cell with Li,and shows an excellent rate and cycling performance when applied in a full cell with LiFePO4 as the cathode.
基金supported by the National Natural Science Foundation of China(U2130204)the Joint Funds of the National Key R&D Program of China(2022YFB2502102)+1 种基金the Young Elite Scientists Sponsorship Program by CAST(YESS20200364)the Beijing Outstanding Young Scientists Program(BJJWZYJH01201910007023)。
文摘Aqueous zinc-ion batteries(AZIBs)are pivotal for achieving net-zero goals,yet their commercialization is impeded by zinc dendrites,parasitic reactions,and interfacial instability.Current debates persist on the interplay between zincophilic-hydrophilic and zincophobic-hydrophobic interactions at the anode-electrolyte interface.Herein,a conceptual framework that decouples these competing effects was proposed,enabling the rational design of a dual-layer architecture with an inner zincophilic layer for Zn^(2+)flux homogenization and an outer hydrophobic layer for water shielding.Through in situ and ex situ analyses,the synergistic mechanism was elucidated.During the cycling process,the zincophilic interface guides uniform Zn deposition,while the hydrophobic coating suppresses H_(2)O-induced side reactions.This dual modification achieves a Zn||Cu cell with an unprecedented 99.89%Coulombic efficiency and 975-cycle stability.This work resolves the long-standing controversy over interfacial affinity design,offering a scalable and industrially viable strategy to enhance AZIBs’durability without sacrificing energy density.
基金National Natural Science Foundation of China,Grant/Award Numbers:22179008,21875022Yibin“Jie Bang Gua Shuai”,Grant/Award Number:2022JB004+2 种基金Beijing Nova Program,Grant/Award Number:20230484241Postdoctoral Fellowship Program of CPSF,Grant/Award Number:GZB20230931Special Support of Chongqing Postdoctoral Research Project,Grant/Award Number:2023CQBSHTB2041。
文摘The burgeoning growth in electric vehicles and portable energy storage systems necessitates advances in the energy density and cost-effectiveness of lithium-ion batteries(LIBs),areas where lithium-rich manganese-based oxide(LLO)materials naturally stand out.Despite their inherent advantages,these materials encounter significant practical hurdles,including low initial Coulombic efficiency(ICE),diminished cycle/rate performance,and voltage fading during cycling,hindering their widespread adoption.In response,we introduce an ionic-electronic dual-conductive(IEDC)surface control strategy that integrates an electronically conductive graphene framework with an ionically conductive heteroepitaxial spinel Li_(4)Mn_(5)O_(12)layer.Prolonged electrochemical and structural analyses demonstrate that this IEDC heterostructure effectively minimizes polarization,mitigates structural distortion,and enhances electronic/ionic diffusion.Density functional theory calculations highlight an extensive Li^(+)percolation network and lower Li^(+)migration energies at the layered-spinel interface.The designed LLO cathode with IEDC interface engineering(LMOSG)exhibits improved ICE(82.9%at 0.1 C),elevated initial discharge capacity(296.7 mAh g^(-1)at 0.1 C),exceptional rate capability(176.5 mAh g^(-1)at 5 C),and outstanding cycle stability(73.7%retention at 5 C after 500 cycles).These findings and the novel dual-conductive surface architecture design offer promising directions for advancing highperformance electrode materials.
基金supported by The Key R&D Program of Heilongjiang province(2023ZX04A01)The Key Project of Chongqing Technology Innovation and Application Development(2022TIAD‐DEX0024,2023TIAD‐KPX0007)+2 种基金The National Key R&D Program of China(2021YFC2902905)the Beijing Nova Program,the Chongqing Outstanding Youth Fund(2022NSCQ‐JQX3895)the National Natural Science Foundation of China(22109010).
文摘Silicon‐based anode materials have garnered considerable attention in lithium‐ion batteries(LIBs)due to their exceptionally high theoretical capacity and energy density.However,intrinsic challenges,such as significant volumetric expansion and the consequent degradation in cycling stability,severely hinder their practical application.As a result,development of silicon anodes that can effectively mitigate volumetric expansions,enhance cycling durability,and improve rate performance has emerged as a critical research focus.However,due to neglect of“size effects”,the modification strategy of silicon‐based electrodes lacks systematic,scientific,and comprehensive guidance.Herein,this review starts from the“size effect”of silicon‐based materials,and reveals in depth the different failure mechanisms of nano‐silicon(Si NPs)and micro‐silicon(μSi).Furthermore,this review provides targeted classification of modification strategies for Si NPs andμSi,and reviews comprehensively,in detail,and in depth the latest research progress on silicon‐based materials.In addition,the review also comprehensively summarizes the cutting‐edge dynamics of matching silicon‐based electrodes with solid electrolytes to construct high‐energy LIBs.It is hoped that this review can provide comprehensive and systematic scientific guidance for modification strategies of silicon‐based electrodes,which is of great significance for promoting the industrialization process of silicon‐based electrodes in high‐energy LIBs.
基金supported by the National Natural Science Foundation of China(52372049)Yunnan Fundamental Research Projects(202301AW070016)+2 种基金China Postdoctoral Science Foundation(Certificate Number:2023M743573)Postdoctoral Fellowship Program of CPSF(GZC20232744)Project of Xingdian Talent Support Plan.
文摘The great interest of Fe-N/C based Zn-air batteries and fuel cells intrigues large numbers of studies on modulating the pore structure for fast mass transport and the electronic structure of atomic Fe centers for enhancing intrinsic activity for oxygen reduction reaction(ORR).A Zn-assisted strategy herein is developed to synthesize a honeycomb-like micro-nanoscale porous Fe-N/C catalyst with atomic FeN_(3)Cl active sites.Specifically,Zn-guided synthesis of honeycomb-like porous carbon supported ZnO,ZnO-templated assembly of hemin modified ZIF-8 on honeycomb-like carbon and Zn/ZnO-assisted pyrolysis of the ZIF-8 precursor are involved.The synthetic mechanism is revealed by in-situ transmission electron microscopy imaging and in-situ X-ray diffraction analysis.Density functional theory calculations demonstrate FeN_(3)Cl can prominently lower the ORR energy barrier on the Fe centers,greatly facilitating catalytic kinetics.Hence,high ORR performance,including half-wave potentials of 0.81 V in acidic conditions and 0.91 V under alkaline media,is achieved.Besides,Zn-air batteries and H_(2)-O_(2)fuel cells base on the resulting catalyst are investigated,also exhibiting excellent battery/cell performances.This study provides a novel strategy for the preparation of honeycomb-like micro-nanoscale porous single-atom catalysts as well as a significant new insight on the catalytic mechanisms,helping to advance in energy devices.
基金supported by the National Natural Science Foundation of China(22179008)support from the Beijing Nova Program(20230484241)+1 种基金support from the China Postdoctoral Science Foundation(2024M754084)the Postdoctoral Fellowship Program of CPSF(GZB20230931)。
文摘The rapid expansion of the automotive sector has significantly increased the demand for highperformance lithium-ion batteries,positioning Ni-rich layered cathodes as a promising solution due to their high energy density and cost-efficiency.However,these cathodes face critical challenges,including thermal instability and structural degradation at an elevated temperature,which hinder their practical application.This study introduces an advanced surface reconstruction strategy combining a LiScF_(4)coating,Sc/F surface co-doping,and a cation-mixing layer to address these issues.The LiScF_(4)coating serves as a durable protective barrier,reducing electrolyte decomposition,minimizing transition metal dissolution,and enhancing lithium-ion transport.Sc/F surface co-doping stabilizes lattice oxygen by increasing the energy barrier for oxygen vacancy formation and minimizing oxygen release,thereby suppressing phase transitions and interfacial side reactions.Additionally,the cation-mixing layer improves interfacial stability by alleviating lattice strain and supporting reversible cation migration,ensuring prolonged durability during cycling and under high-temperature conditions.These integrated modifications work synergistically to mitigate various degradation mechanisms,significantly improving the thermal stability,structural integrity,and electrochemical performance of Ni-rich cathodes.This approach offers a viable pathway for incorporating Ni-rich cathodes into advanced lithium-ion batteries,making them well-suited for applications requiring high thermal stability.Moreover,this research provides valuable guidance for the development of a multi-component modification strategy,paving the way for future innovations in energy storage materials and advancing high-performance battery technology.
基金supported by the National Natural Science Foundation of China(22179005,92372207)Fundamental Research Funds for the Central Universities(2022CX01017).
文摘Lithium metal is a compelling choice as an anode material for high-energy-density batteries,attributed to its elevated theoretical specific energy and low redox potential.Nevertheless,challenges arise due to its susceptibility to high-volume changes and the tendency for dendritic development during cycling,leading to restricted cycle life and diminished Coulombic efficiency(CE).Here,we innovatively engineered a kind of porous biocarbon to serve as the framework for a lithium metal anode,which boasts a heightened specific surface area and uniformly dispersed ZnO active sites,directly derived from metasequoia cambium.The porous structure efficiently mitigates local current density and alleviates the volume expansion of lithium.Also,incorporating the ZnO lithiophilic site notably reduces the nucleation overpotential to a mere 16 mV,facilitating the deposition of lithium in a compact form.As a result,this innovative material ensures an impressive CE of 98.5%for lithium plating/stripping over 500 cycles,a remarkable cycle life exceeding 1200 h in a Li symmetrical cell,and more than 82%capacity retention ratio after an astonishing 690 cycles in full cells.In all,such a rationally designed Li composite anode effectively mitigates volume change,enhances lithophilicity,and reduces local current density,thereby inhibiting dendrite formation.The preparation of a highperformance lithium anode frame proves the feasibility of using biocarbon in a lithium anode frame.
