Relaxor ferroelectric polymers display great potential in capacitor dielectric applications because of their excellent flexibility,light weight,and high dielectric constant.However,their electrical energy storage capa...Relaxor ferroelectric polymers display great potential in capacitor dielectric applications because of their excellent flexibility,light weight,and high dielectric constant.However,their electrical energy storage capacity is limited by their high conduction losses and low dielectric strength,which primarily originates from the impact-ionization-induced electron multiplication,low mechanical modulus,and low thermal conductivity of the dielectric polymers.Here a matrix free strategy is developed to effectively suppress electron multiplication effects and to enhance mechanical modulus and thermal conductivity of a dielectric polymer,which involves the chemical adsorption of an electron barrier layer on boron nitride nanosheet surfaces by chemically adsorbing an amino-containing polymer.A dramatic decrease of leakage current(from 2.4×10^(-6)to 1.1×10^(-7)A cm^(-2)at 100 MV m^(-1))and a substantial increase of breakdown strength(from 340 to 742 MV m^(-1))were achieved in the nanocompostes,which result in a remarkable increase of discharge energy density(from 5.2 to 31.8 J cm^(-3)).Moreover,the dielectric strength of the nanocomposites suffering an electrical breakdown could be restored to 88%of the original value.This study demonstrates a rational design for fabricating dielectric polymer nanocomposites with greatly enhanced electric energy storage capacity.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supported by the National Natural Science Foundation of China(52003153,51877132 and 52002300)Program of Shanghai Academic Research Leader(21XD1401600)+1 种基金State Key Laboratory of Electrical Insulation and Power Equipment(EIPE20203,EIPE21206)the Major Research Plan of National Natural Science Foundation of China(92066103)。
文摘Relaxor ferroelectric polymers display great potential in capacitor dielectric applications because of their excellent flexibility,light weight,and high dielectric constant.However,their electrical energy storage capacity is limited by their high conduction losses and low dielectric strength,which primarily originates from the impact-ionization-induced electron multiplication,low mechanical modulus,and low thermal conductivity of the dielectric polymers.Here a matrix free strategy is developed to effectively suppress electron multiplication effects and to enhance mechanical modulus and thermal conductivity of a dielectric polymer,which involves the chemical adsorption of an electron barrier layer on boron nitride nanosheet surfaces by chemically adsorbing an amino-containing polymer.A dramatic decrease of leakage current(from 2.4×10^(-6)to 1.1×10^(-7)A cm^(-2)at 100 MV m^(-1))and a substantial increase of breakdown strength(from 340 to 742 MV m^(-1))were achieved in the nanocompostes,which result in a remarkable increase of discharge energy density(from 5.2 to 31.8 J cm^(-3)).Moreover,the dielectric strength of the nanocomposites suffering an electrical breakdown could be restored to 88%of the original value.This study demonstrates a rational design for fabricating dielectric polymer nanocomposites with greatly enhanced electric energy storage capacity.
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)).
