PVDF-based nanocomposites have gained significant focus in capacitors for their excellent dielectric strength, its multi-scale structural inhomogeneity is the bottleneck for improving the energy storage performance. H...PVDF-based nanocomposites have gained significant focus in capacitors for their excellent dielectric strength, its multi-scale structural inhomogeneity is the bottleneck for improving the energy storage performance. Here, the composite components are optimized by the matrix modification,BST(Ba_(0.6)Sr_(0.4)TiO_(3)) ceramic fibrillation and surface coating. A series of PVDF/polymethyl methacrylate/lysozyme@BST nanofibers with continuous gradient distribution(PF-M/m BST nf-g) are prepared by the concentration gradient-biaxial high-speed electrospinning. The finite element simulation and experiment results indicate that the continuous gradient structure is favorable for the microstructure and inhomogeneity of the electric field distribution, significantly increasing the breakdown strength(Eb) and the permittivity(εr), as well as effectively suppressing the interfacial injected charge and leakage current. As a result, the energy storage density(Ue) of 23.1 J/cm^(3)at 600 MV/m with the charge-discharge efficiency(η) of 71% is achieved compared to PF-M(5.6 J/cm^(3)@350 MV/m, 65%). The exciting energy storage performance based on the well-designed PF-M/m BST nf-g provides important information for the development and application of polymer nanocomposite dielectrics.展开更多
Composite polymer electrolytes(CPEs)are considered as promising electrolytes for next-generation lithium batteries due to their superior advantages in safety,mechanical stability/flexibility,cathode compatibility,etc....Composite polymer electrolytes(CPEs)are considered as promising electrolytes for next-generation lithium batteries due to their superior advantages in safety,mechanical stability/flexibility,cathode compatibility,etc.However,achieving high Li+conductivity remains a major challenge,particularly at low temperatures.A key obstacle lies in the limited understanding of the complex interplay among amorphous components,including fillers,plasticizers,and residual solvents,which significantly hampers the rational design of high-performing CPEs.In this contribution,a polyvinylidene fluoride(PVDF)-based composite electrolyte has been developed,exhibiting high room-temperature ionic conductivity/mobility(>1 mS cm^(-1)/0.95×10^(-11)m^(2)s^(-1)),along with excellent electrochemical performances,including a wide stability window(4.8 V vs.Li/Li^(+)),superior charge/discharge capacity,and reversibility.By performing advanced solid-state nuclear magnetic resonance(ssNMR)techniques,in combination with systematic investigations into solid polymer electrolytes(SPEs),gel polymer electrolytes(GPEs),and CPEs,we establish an efficient NMR-based strategy for deconvoluting the structural and dynamic features of complex electrolyte systems.Notably,the simple1H magic-angle spinning(MAS)NMR spectroscopy enables the identification and monitoring of nearly all components in the composite matrix.Motion-sensitive1H-13C and1H-7Li correlation experiments further reveal that the rigidity of PVDF polymer chain segments and the presence of residual solvents are two critical factors governing Li+mobility.Moreover,we demonstrate that the order of the filler and plasticizer addition during the CPE fabrication significantly influences the performance of the electrolyte by regulating the retention of residual solvents.This work not only provides molecular-level insights into the structure-ion mobility relationships in the PVDF-based CPEs but also establishes a general NMR-based characterization approach for investigating other complex composite electrolyte materials.展开更多
Fluorinated polymers are important materials that are widely used in many areas as taking the advantage of inertness to chemical corrosion,prominent weather resista nee,low flammability,and good thermal stability.Poly...Fluorinated polymers are important materials that are widely used in many areas as taking the advantage of inertness to chemical corrosion,prominent weather resista nee,low flammability,and good thermal stability.Poly(vinylidene fluoride)(PVDF)based fluoropolymers is the most commontype of commercial fluoropolymer especially used as dielectric materials.However,there are always some shortcomings in practical applications,so it is necessary to modify PVDF-based fluoropolymers for better application.Controlled/living radical polymerization(CRP)and related techniques have become a powerful approach to tailoring the chemical and physical properties of materials and have given rise to great advances in modification of PVDF-based fluoropolymers.展开更多
Iron difluoride(FeF_(2))is considered a highcapacity cathode material for lithium-ion batteries.However,its specific capacity and stability are limited by the poor electrochemical kinetics of conversion reactions.Here...Iron difluoride(FeF_(2))is considered a highcapacity cathode material for lithium-ion batteries.However,its specific capacity and stability are limited by the poor electrochemical kinetics of conversion reactions.Herein,the conversion reaction is confined in a localized nanosized space by encapsulating FeF_(2) nanoparticles in polymer gelatin.The FeF_(2) nanocrystal-coated polyvinylidene fluoride-based layer(defined as Fe F_(2) @100%G-40%P)was synthesized by glucoseassisted in-situ gelatinization to construct an artificial cathode solid electrolyte interphase via a solvothermal process.Thanks to the improved kinetics of the localized conversion reaction,the obtained FeF_(2) @100%G-40%P electrodes show good cyclic stability(313mAhg^(-1) after 150 cycles at 100 mAg^(-1) ,corresponding to a retention of 80%)and a high rate performance(186.6 mAhg^(-1) at 500 mAg^(-1)).展开更多
基金the support and funding from the National Natural Science Foundation of China (Nos. 51773164, 5186020071)Ningxia Natural Science Foundation (No. 2023AAC03104)。
文摘PVDF-based nanocomposites have gained significant focus in capacitors for their excellent dielectric strength, its multi-scale structural inhomogeneity is the bottleneck for improving the energy storage performance. Here, the composite components are optimized by the matrix modification,BST(Ba_(0.6)Sr_(0.4)TiO_(3)) ceramic fibrillation and surface coating. A series of PVDF/polymethyl methacrylate/lysozyme@BST nanofibers with continuous gradient distribution(PF-M/m BST nf-g) are prepared by the concentration gradient-biaxial high-speed electrospinning. The finite element simulation and experiment results indicate that the continuous gradient structure is favorable for the microstructure and inhomogeneity of the electric field distribution, significantly increasing the breakdown strength(Eb) and the permittivity(εr), as well as effectively suppressing the interfacial injected charge and leakage current. As a result, the energy storage density(Ue) of 23.1 J/cm^(3)at 600 MV/m with the charge-discharge efficiency(η) of 71% is achieved compared to PF-M(5.6 J/cm^(3)@350 MV/m, 65%). The exciting energy storage performance based on the well-designed PF-M/m BST nf-g provides important information for the development and application of polymer nanocomposite dielectrics.
基金financially supported by the National Natural Science Foundation of China(Grant No.22325405,22432005,22321002,and 22404159)the Dalian Science and Technology Talent Innovation Program(Grant No.2024RG009)+2 种基金the China Postdoctoral Science Foundation(Grant Number 2024M753120)the LiaoNing Revitalization Talents Program(XLYC2203134)the ANSO Scholarship for Young Talents for financial support。
文摘Composite polymer electrolytes(CPEs)are considered as promising electrolytes for next-generation lithium batteries due to their superior advantages in safety,mechanical stability/flexibility,cathode compatibility,etc.However,achieving high Li+conductivity remains a major challenge,particularly at low temperatures.A key obstacle lies in the limited understanding of the complex interplay among amorphous components,including fillers,plasticizers,and residual solvents,which significantly hampers the rational design of high-performing CPEs.In this contribution,a polyvinylidene fluoride(PVDF)-based composite electrolyte has been developed,exhibiting high room-temperature ionic conductivity/mobility(>1 mS cm^(-1)/0.95×10^(-11)m^(2)s^(-1)),along with excellent electrochemical performances,including a wide stability window(4.8 V vs.Li/Li^(+)),superior charge/discharge capacity,and reversibility.By performing advanced solid-state nuclear magnetic resonance(ssNMR)techniques,in combination with systematic investigations into solid polymer electrolytes(SPEs),gel polymer electrolytes(GPEs),and CPEs,we establish an efficient NMR-based strategy for deconvoluting the structural and dynamic features of complex electrolyte systems.Notably,the simple1H magic-angle spinning(MAS)NMR spectroscopy enables the identification and monitoring of nearly all components in the composite matrix.Motion-sensitive1H-13C and1H-7Li correlation experiments further reveal that the rigidity of PVDF polymer chain segments and the presence of residual solvents are two critical factors governing Li+mobility.Moreover,we demonstrate that the order of the filler and plasticizer addition during the CPE fabrication significantly influences the performance of the electrolyte by regulating the retention of residual solvents.This work not only provides molecular-level insights into the structure-ion mobility relationships in the PVDF-based CPEs but also establishes a general NMR-based characterization approach for investigating other complex composite electrolyte materials.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.92066204,52003214,51773166 and 51603167)China Postdoctoral Science Foundation Funded Project(Nos.2019M663699 and 2020T130507)+3 种基金Key Laboratory Construction Program of Xi'an Municipal Bureau of Science and Technology(No.201805056ZD7CG40)Natural Science Foundation of Jiangsu Province(No.BK2020245)Suzhou Science and Technology Project(No.SYG202028)the Fundamental Research Funds for the Central Universities(No.xzy012020035).
文摘Fluorinated polymers are important materials that are widely used in many areas as taking the advantage of inertness to chemical corrosion,prominent weather resista nee,low flammability,and good thermal stability.Poly(vinylidene fluoride)(PVDF)based fluoropolymers is the most commontype of commercial fluoropolymer especially used as dielectric materials.However,there are always some shortcomings in practical applications,so it is necessary to modify PVDF-based fluoropolymers for better application.Controlled/living radical polymerization(CRP)and related techniques have become a powerful approach to tailoring the chemical and physical properties of materials and have given rise to great advances in modification of PVDF-based fluoropolymers.
基金supported by the Science and Technology Commission of Shanghai Municipality(20520710400,19JC1412600 and 18230743400)the National Natural Science Foundation of China(21771124 and 21901156)+1 种基金the Oceanic Interdisciplinary Program(SL2020MS020)the SJTU-Warwick Joint Seed Fund(2019/20)of Shanghai Jiao Tong University。
文摘Iron difluoride(FeF_(2))is considered a highcapacity cathode material for lithium-ion batteries.However,its specific capacity and stability are limited by the poor electrochemical kinetics of conversion reactions.Herein,the conversion reaction is confined in a localized nanosized space by encapsulating FeF_(2) nanoparticles in polymer gelatin.The FeF_(2) nanocrystal-coated polyvinylidene fluoride-based layer(defined as Fe F_(2) @100%G-40%P)was synthesized by glucoseassisted in-situ gelatinization to construct an artificial cathode solid electrolyte interphase via a solvothermal process.Thanks to the improved kinetics of the localized conversion reaction,the obtained FeF_(2) @100%G-40%P electrodes show good cyclic stability(313mAhg^(-1) after 150 cycles at 100 mAg^(-1) ,corresponding to a retention of 80%)and a high rate performance(186.6 mAhg^(-1) at 500 mAg^(-1)).
