With the increasing market demand for high-performance lithium-ion batteries with high-capacity electrode materials,reducing the irreversible capacity loss in the initial cycle and compensating for the active lithium ...With the increasing market demand for high-performance lithium-ion batteries with high-capacity electrode materials,reducing the irreversible capacity loss in the initial cycle and compensating for the active lithium loss during the cycling process are critical challenges.In recent years,various prelithiation strategies have been developed to overcome these issues.Since these approaches are carried out under a wide range of conditions,it is essential to evaluate their suitability for large-scale commercial applications.In this review,these strategies are categorized based on different battery assembling stages that they are implemented in,including active material synthesis,the slurry mixing process,electrode pretreatment,and battery fabrication.Furthermore,their advantages and disadvantages in commercial production are discussed from the perspective of thermodynamics and kinetics.This review aims to provide guidance for the future development of prelithiation strategies toward commercialization,which will potentially promote the practical application of next-generation high-energy-density lithium-ion batteries.展开更多
The form-stable paraffin/high-density polyethylene/expanded graphite/epoxy resin composite phase change materials(CPCMs),exhibiting suitable thermal properties,including low melting temperature,high conductivity and h...The form-stable paraffin/high-density polyethylene/expanded graphite/epoxy resin composite phase change materials(CPCMs),exhibiting suitable thermal properties,including low melting temperature,high conductivity and high phase change enthalpy,was developed in this work.Herein,paraffin(PA)was utilized as a core PCM.High-density polyethylene(HDPE)was utilized for the shape stabilization and preventing the PCMs leakage.Expanded graphite(EG)was used to increase its thermal conductivity and act also in the porous supporting material.Epoxy resin(ER)was used to provide flexible encapsulated scaffold morphology and keep a highly tight network structure of the PCMs.However,the physical architecture,the chemical architecture and thermal behavior properties of specimens were investigated by using the spectroscopy and calorimetry techniques.The scanning electron microscope(SEM),X-ray diffraction(XRD)and fourier transform infrared spectrometer FTIR tests have shown good uniformity structure and good compatibility of components.In addition,the thermal conductivity tests revealed that the thermal conductivity of PA,initially 0.31 W/(m·K)improved up to 1.9 times by adding the 6 wt%mass fraction of EG in composite PCMs.Furthermore,the differential scanning calorimeter(DSC)measurements indicated that PA melting enthalpy,initially 231 J/g decreased up to 125 J/g with the increase of the amount of HDPE which was due to the limitation caused by the atomic network constructed by the base material.The thermogravimetric analyzer(TGA)and leakage-proof revealed the enhancement of the degradation of PA with the raise of amount of the HDPE into the CPCMs.Therefore,the proposed form-stable CPCMs are a great candidate for the thermal regulation and thermal energy storage employment.展开更多
Organic scintillators,materials with the ability to exhibit luminescence when exposed to X-rays,have aroused increasing interest in recent years.However,the enhancement of radioluminescence and improving X-ray absorpt...Organic scintillators,materials with the ability to exhibit luminescence when exposed to X-rays,have aroused increasing interest in recent years.However,the enhancement of radioluminescence and improving X-ray absorption of organic scintillators lie in the inherent dilemma,due to the waste of triplet excitons and weak X-ray absorption during scintillation.Here,we employ halogenated thermally activated delayed fluorescence materials to improve the triplet exciton utilization and X-ray absorption simultaneously,generating efficient scintillation with a low detection limit,which is one order of magnitude lower than the dosage for X-ray medical diagnostics.Through experimental study and theoretical calculation,we reveal the positive role of X-ray absorption,quantum yields of prompt fluorescence,and intersystem crossing in promoting the radioluminescence intensity.This finding offers an opportunity to design diverse types of organic scintillators and expands the applications of thermally activated delayed fluorescence.展开更多
基金Soft Science Research Project of Guangdong Province,Grant/Award Number:2017B030301013Shenzhen Science and Technology Research Grant,Grant/Award Number:JCYJ20200109140416788。
文摘With the increasing market demand for high-performance lithium-ion batteries with high-capacity electrode materials,reducing the irreversible capacity loss in the initial cycle and compensating for the active lithium loss during the cycling process are critical challenges.In recent years,various prelithiation strategies have been developed to overcome these issues.Since these approaches are carried out under a wide range of conditions,it is essential to evaluate their suitability for large-scale commercial applications.In this review,these strategies are categorized based on different battery assembling stages that they are implemented in,including active material synthesis,the slurry mixing process,electrode pretreatment,and battery fabrication.Furthermore,their advantages and disadvantages in commercial production are discussed from the perspective of thermodynamics and kinetics.This review aims to provide guidance for the future development of prelithiation strategies toward commercialization,which will potentially promote the practical application of next-generation high-energy-density lithium-ion batteries.
基金This research was financially supported by the National Natural Science Foundation of China(52206087,52130607)the Natural Science Foundation of Gansu Province,China(20JR10RA193)+2 种基金the Industrial Support Plan Project of Gansu Provincial Education Department(2022CYZC-21,2021CYZC-27)the Doctoral Research Funds of Lanzhou University of Technology(061907)the Red Willow Excellent Youth Project of Lanzhou University of Technology.
文摘The form-stable paraffin/high-density polyethylene/expanded graphite/epoxy resin composite phase change materials(CPCMs),exhibiting suitable thermal properties,including low melting temperature,high conductivity and high phase change enthalpy,was developed in this work.Herein,paraffin(PA)was utilized as a core PCM.High-density polyethylene(HDPE)was utilized for the shape stabilization and preventing the PCMs leakage.Expanded graphite(EG)was used to increase its thermal conductivity and act also in the porous supporting material.Epoxy resin(ER)was used to provide flexible encapsulated scaffold morphology and keep a highly tight network structure of the PCMs.However,the physical architecture,the chemical architecture and thermal behavior properties of specimens were investigated by using the spectroscopy and calorimetry techniques.The scanning electron microscope(SEM),X-ray diffraction(XRD)and fourier transform infrared spectrometer FTIR tests have shown good uniformity structure and good compatibility of components.In addition,the thermal conductivity tests revealed that the thermal conductivity of PA,initially 0.31 W/(m·K)improved up to 1.9 times by adding the 6 wt%mass fraction of EG in composite PCMs.Furthermore,the differential scanning calorimeter(DSC)measurements indicated that PA melting enthalpy,initially 231 J/g decreased up to 125 J/g with the increase of the amount of HDPE which was due to the limitation caused by the atomic network constructed by the base material.The thermogravimetric analyzer(TGA)and leakage-proof revealed the enhancement of the degradation of PA with the raise of amount of the HDPE into the CPCMs.Therefore,the proposed form-stable CPCMs are a great candidate for the thermal regulation and thermal energy storage employment.
基金This work was financially supported by the National Key R&D Program of China(grant no.2020YFA0709900)National Basic Science Center of Flexible Electronics(62288102)+1 种基金the National Natural Science Foundation of China(62134007,21975120,21875104,and 21973043)the Primary Research and Development Plan of Jiangsu Province(BE2016770).
文摘Organic scintillators,materials with the ability to exhibit luminescence when exposed to X-rays,have aroused increasing interest in recent years.However,the enhancement of radioluminescence and improving X-ray absorption of organic scintillators lie in the inherent dilemma,due to the waste of triplet excitons and weak X-ray absorption during scintillation.Here,we employ halogenated thermally activated delayed fluorescence materials to improve the triplet exciton utilization and X-ray absorption simultaneously,generating efficient scintillation with a low detection limit,which is one order of magnitude lower than the dosage for X-ray medical diagnostics.Through experimental study and theoretical calculation,we reveal the positive role of X-ray absorption,quantum yields of prompt fluorescence,and intersystem crossing in promoting the radioluminescence intensity.This finding offers an opportunity to design diverse types of organic scintillators and expands the applications of thermally activated delayed fluorescence.
