With excellent energy densities and highly safe performance,solidstate lithium batteries(SSLBs)have been hailed as promising energy storage devices.Solid-state electrolyte is the core component of SSLBs and plays an e...With excellent energy densities and highly safe performance,solidstate lithium batteries(SSLBs)have been hailed as promising energy storage devices.Solid-state electrolyte is the core component of SSLBs and plays an essential role in the safety and electrochemical performance of the cells.Composite polymer electrolytes(CPEs)are considered as one of the most promising candidates among all solid-state electrolytes due to their excellent comprehensive performance.In this review,we briefly introduce the components of CPEs,such as the polymer matrix and the species of fillers,as well as the integration of fillers in the polymers.In particular,we focus on the two major obstacles that affect the development of CPEs:the low ionic conductivity of the electrolyte and high interfacial impedance.We provide insight into the factors influencing ionic conductivity,in terms of macroscopic and microscopic aspects,including the aggregated structure of the polymer,ion migration rate and carrier concentration.In addition,we also discuss the electrode-electrolyte interface and summarize methods for improving this interface.It is expected that this review will provide feasible solutions for modifying CPEs through further understanding of the ion conduction mechanism in CPEs and for improving the compatibility of the electrode-electrolyte interface.展开更多
Substituting liquid electrolytes with solid elec-trolytes is considered as an important strategy to solve the problem of flammability and explosion for traditional lithium-ion batteries(LIB).However,neither inorganic ...Substituting liquid electrolytes with solid elec-trolytes is considered as an important strategy to solve the problem of flammability and explosion for traditional lithium-ion batteries(LIB).However,neither inorganic solid electrolytes(ISE)nor solid polymer electrolytes(SPE)alone can meet the operating requirements for room-temperature(RT)all-solid-state lithium metal batteries(ASSLMB).Here,we report a three-dimensional(3D)nanofiber framework reinforced polyethylene oxide(PEO)-based composite polymer electrolytes(CPE)through con-structing a nanofiber framework combining polyacryloni-trile(PAN)and fast Li-ion conductor Li_(0.33)La_(0.557)TiO_(3)(LLTO)framework by electrospinning method.Mean-while,the PEO electrolyte filled in the pores of the PAN/LLTO nanofiber framework can effectively isolate the direct contact between the chemically active Ti^(4+)in LLTO with lithium metal,thereby avoiding the occurrence of interfacial reactions.Enhanced electrochemical stability makes a wide electrochemical window up to 4.8 V with an ionic conductivity of about 9.87×10^(-5)S·cm^(-1)at RT.Benefiting from the excellent lithium dendrite growth inhibition ability of 3D PAN/LLTO nanofiber framework,especially when the mass of LLTO reaches twice that of the PAN,Li/Li symmetric cell could cycle stably for 1000 h without a short circuit.In addition,under 30℃,the LiFePO_(4)/Li ASSLMB using such CPE delivers large capacities of 156.2 and 140 mAh·g^(-1)at 0.2C and 0.5C,respectively.These results provide a new insight for the development of the next generation of safe,high-perfor-mance ASSLMBs.展开更多
Nano-La2O3 was modified with the vinyltrimethoxylsilane by hydrolysis and a novel poly （vinylidene fluoride-co-hexafluoropropylene） （PVDF-HFP） based composite polymer electrolyte doped with the modified nano-La2O3...Nano-La2O3 was modified with the vinyltrimethoxylsilane by hydrolysis and a novel poly （vinylidene fluoride-co-hexafluoropropylene） （PVDF-HFP） based composite polymer electrolyte doped with the modified nano-La2O3 was prepared by phase inversion method. The physicochemical properties were studied by SEM, FT-IR, XRD, TG and electrochemical methods. The results of FT-IR indicated that the nano-La2O3 was successfully modified with vinyltrimethoxylsilane. The XRD analysis showed that the incorporation of modified nano-La2O3 into the polymer electrolyte membranes could effectively reduce the crystallinity of PVDF-HFP, and the characterizations also suggested that thermal stability and electrochemical stability window could reach to 382°C and 5.1V, respectively; the reciprocal temperature dependence of ionic conductivity followed Vogel-Tamman-Fulcher （VTF） relation, ionic conductivity at room temperature was up to 3.5×10-3S/cm and lithium ions transference number was up to 0.42; the interfacial resistance increased at initial value about353Ω/cm2 and reached a steady value about 559Ω/cm2 after 5d storage at 30°C. The fabricated Li/As-prepared electrolytes/LiCoO2 coin cell showed excellent rate and cycle performances.展开更多
(PEO)8LiClO4-SiO2 composite polymer electrolytes(CPEs)were prepared by in-situ reaction,in which ethyl-orthosilicate(TEOS)was catalyzed by HCl and NH3.H2O,respectively.The ionic conductivity,the contact angle and the ...(PEO)8LiClO4-SiO2 composite polymer electrolytes(CPEs)were prepared by in-situ reaction,in which ethyl-orthosilicate(TEOS)was catalyzed by HCl and NH3.H2O,respectively.The ionic conductivity,the contact angle and the morphology of inorganic particles in the CPEs were investigated by AC impedance spectra,contact angle method and TEM.The conductivities of acid-catalyzed CPE and alkali-catalyzed CPE are 2.2×10-5and 1.1×10-5S/cm respectively at 30℃.The results imply that the catalyst plays an important role in the structure of in-situ preparation of SiO2,and influences the surface energy and conductivity of CPE films directly.Meanwhile,the ionic conductivity is related to the surface energy.展开更多
The lithiated covalent organic framework(named TpPa-SO_(3) Li),which was prepared by a mild chemical lithiation strategy,was introduced in poly(ethylene oxide)(PEO)to produce the composite polymer electrolytes(CPEs).L...The lithiated covalent organic framework(named TpPa-SO_(3) Li),which was prepared by a mild chemical lithiation strategy,was introduced in poly(ethylene oxide)(PEO)to produce the composite polymer electrolytes(CPEs).Li-ion can transfer along the PEO chain or across the layer of TpPa-SO_(3) Li within the nanochannels,resulting in a high Li-ion conductivity of3.01×10^(-4)S/cm at 60℃.When the CPE with 0.75 wt.%TpPa-SO_(3) Li was used in the LiFePO_(4)‖Li solid-state battery,the cell delivered a stable capacity of 125 mA·h/g after 250 cycles at 0.5 C,60℃.In comparison,the cell using the CPE without TpPa-SO_(3) Li exhibited a capacity of only 118 mA·h/g.展开更多
Low-cost and flexible solid polymer electrolytes are promising in all-solid-state Li-metal batteries with high energy density and safety.However,both the low room-temperature ionic conductivities and the small Li^(+)t...Low-cost and flexible solid polymer electrolytes are promising in all-solid-state Li-metal batteries with high energy density and safety.However,both the low room-temperature ionic conductivities and the small Li^(+)transference number of these electrolytes significantly increase the internal resistance and overpotential of the battery.Here,we introduce Gd-doped CeO_(2) nanowires with large surface area and rich surface oxygen vacancies to the polymer electrolyte to increase the interaction between Gd-doped CeO_(2) nanowires and polymer electrolytes,which promotes the Li-salt dissociation and increases the concentration of mobile Li ions in the composite polymer electrolytes.The optimized composite polymer electrolyte has a high Li-ion conductivity of 5×10^(-4)4 S cm^(-1) at 30℃ and a large Li+transference number of 0.47.Moreover,the composite polymer electrolytes have excellent compatibility with the metallic lithium anode and high-voltage LiNi_(0.8)Mn _(0.1)Co_(0.1)O_(2)(NMC)cathode,providing the stable cycling of all-solid-state batteries at high current densities.展开更多
PEO-LiClO4-TiO2 composite polymer electrolyte films were prepared. TiO2 was formed directly in matrix by hydrolysis and condensation reaction of tetrabutyl titanate. The crystallinity, morphology and ionic conductivit...PEO-LiClO4-TiO2 composite polymer electrolyte films were prepared. TiO2 was formed directly in matrix by hydrolysis and condensation reaction of tetrabutyl titanate. The crystallinity, morphology and ionic conductivity of composite polymer electrolyte films were examined by differential scanning calorimetry, scanning electron microscopy, atom force microscopy and alternating current impedance spectroscopy, respectively. The glass transition temperature and the crystallinity of composite polymer electrolytes are decreased compared with those of PEO-LiClO4 polymer electrolyte film. The results show that TiO2 particles are uniformly dispersed in PEO-LiClO4-5%TiO2 composite polymer electrolyte film. The maximal conductivity of 5.5×10、5 Scm at 20 ℃ of PEO-LiClO4-TiO2 film is obtained at 5% mass fraction of TiO2.展开更多
We present an empirical model for the effective thermal conductivity (ETC) of a polymer composite that includes dependency on the filler size distribution-chosen as the Rosin-Rammler distribution. The ETC is determine...We present an empirical model for the effective thermal conductivity (ETC) of a polymer composite that includes dependency on the filler size distribution-chosen as the Rosin-Rammler distribution. The ETC is determined based on certain hypotheses that connect the behavior of a real composite material A, to that of a model composite material B, filled with mono-dimensional filler. The application of these hypotheses to the Maxwell model for ETC is presented. The validation of the new model and its characteristic equation was carried out using experimental data from the reference. The comparison showed that by using the size distribution law a very good fit between the equation of the new model (the size distribution model for the ETC) and the reference experimental results is obtained, even for high volume fractions, up to about 50%.展开更多
Poly（vinylidene fluoride-co-hexafluoropropylene） （PVDF-HFP） based composite polymer electrolyte （CPE） modified with CeO2, La2O3 and Y2O3 nano-rare earth oxides was prepared by phase inversion technique. Physical...Poly（vinylidene fluoride-co-hexafluoropropylene） （PVDF-HFP） based composite polymer electrolyte （CPE） modified with CeO2, La2O3 and Y2O3 nano-rare earth oxides was prepared by phase inversion technique. Physical and chemical properties of the modified CPEs were studied by SEM, TG-DSC and electrochemical methods. The results show that the CPE modified with 10% La2O3 （mass fraction） has the best practical applicability, which indicates that the thermal and electrochemical stability can reach over 400 ℃ and 4.5 V, respectively, and temperature dependence of ionic conductivity follows Vogel-Tamman-Fulcher （VTF） relationship and ionic conductivity at room temperature is up to 3.3 mS/cm. The interfacial resistance Ri reaches a stable value about 557 Ω after 6 d storage.展开更多
Composite polymer electrolytes based on poly（ethylene oxide）-polysiloxane/l-butyl-3-methylimida- zolium bis（trifluoromethanesulfonyl）imide/organomontmorillonite （PEO-PDMS/IL/OMMT） were pre- pared and characteriz...Composite polymer electrolytes based on poly（ethylene oxide）-polysiloxane/l-butyl-3-methylimida- zolium bis（trifluoromethanesulfonyl）imide/organomontmorillonite （PEO-PDMS/IL/OMMT） were pre- pared and characterized. Addition of both an ionic liquid and OMMT to the polymer base of PEO-PDMS resulted in an increase in ionic conductivity. At room temperature, the ionic conductivity of sample PPB 100-OMMT4 was 2.19 × 10-3 S/cm. The composite polymer electrolyte also exhibited high thermal and electrochemical stability and may potentially be applied in lithium batteries.展开更多
To analyze the feasibility of application of composite material as the insulating material, it is necessary to have knowledge of some of its mechanical properties. An insulating material may suffer from the most diffe...To analyze the feasibility of application of composite material as the insulating material, it is necessary to have knowledge of some of its mechanical properties. An insulating material may suffer from the most different efforts, but the major applications suggest mechanical bending and compression tests because the insulation can be applied on roofs of homes, liners similar to, in the form of plates. Thus, the product is continually flexed. When the material is used on a floor, it suffers constant compressions over its use. For tests performed in this study, we used the ASTM D695-96 for compression, an example of literature. Using such a standard test, specimens were produced for compression test, with specimens made of cylindrical shapes, respecting the condition that the height of the specimen corresponds to twice the diameter of the base. Polyurethane castor without charge vermiculite and mass loads of 10%, 15% and 20% matrix： four specimens for each type of material were produced. The composites were tested in a universal testing machine at a speed of 2 mm/s. The results are average values of four test samples, and initially show the behavior of castor oil polyurethane during the compression test, which is detailed in the stress versus strain curve. The achieved results are promising, and detailed in this paper.展开更多
Satisfactory ionic conductivity,excellent mechanical stability,and high-temperature resistance are the prerequisites for the safe application of solid polymer electrolytes(SPEs)in all-solid-state lithium metal batteri...Satisfactory ionic conductivity,excellent mechanical stability,and high-temperature resistance are the prerequisites for the safe application of solid polymer electrolytes(SPEs)in all-solid-state lithium metal batteries(ASSLMBs).In this study,a novel poly(m-phenylene isophthalamide)(PMIA)-core/poly(ethylene oxide)(PEO)-shell nanofiber membrane and the functional Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)ceramic nanopar-ticle are simultaneously introduced into the PEO-based SPEs to prepare composite polymer electrolytes(CPEs).The core PMIA layer of composite nanofibers can greatly improve the mechanical strength and thermal stability of the CPEs,while the shell PEO layer can provide the 3D continuous transport channels for lithium ions.In addition,the introduction of functional LLZTO nanoparticle not only reduces the crys-tallinity of PEO,but also promotes the dissociation of lithium salts and releases more Li^(+)ions through its interaction with the Lewis acid-base of anions,thereby overall improving the transport of lithium ions.Consequently,the optimized CPEs present high ionic conductivity of 1.38×10^(−4)S/cm at 30℃,signifi-cantly improved mechanical strength(8.5 MPa),remarkable thermal stability(without obvious shrinkage at 150℃),and conspicuous Li dendrites blocking ability(>1800 h).The CPEs also both have good com-patibility and cyclic stability with LiFePO_(4)(>2000 cycles)and high-voltage LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NMC811)(>500 cycles)cathodes.In addition,even at low temperature(40℃),the assembled LiFePO4/CPEs/Li bat-tery still can cycle stably.The novel design can provide an effective way to exploit high-performance solid-state electrolytes.展开更多
A novel composite polymer electrolyte was prepared by blending an appropriateamount of LiClO_4 and 10 percent (mass fraction) fumed SiO_2 with the block copolymer of poly(ethylene oxide) (PEO) synthesized by poly (eth...A novel composite polymer electrolyte was prepared by blending an appropriateamount of LiClO_4 and 10 percent (mass fraction) fumed SiO_2 with the block copolymer of poly(ethylene oxide) (PEO) synthesized by poly (ethylene glycol) (PEG) 400 and CH_2C1_2 The ionicconductivity, electrochemical stability, interfacial characteristic and thermal behavior of thecomposite polymer electrolyte were studied by the measurements of AC impedance spectroscopy, linearsweep voltammetry and differential scanning calorimetry (DSC), respectively. The glass transitiontemperature acts as a function of salt concentration, which increases with the LiClO_4 content.Lewis acid-base model interaction mechanism was introduced to interpret the interactive relationbetween the filled fumed SiO_2 and the lithium salt in the composite polymer electrolyte. Over thesalt concentration range and the measured temperature, the maximum ionic conductivity of thecomposite polymer electrolyte (10^(-4.41) S/cm) appeared at EO/Li=25 (mole ratio) and 30 deg C, andthe beginning oxidative degradation potential versus Li beyond 5 V.展开更多
Polymer matrix composites with high dielectric constants and low dielectric losses are in high demand for flexible electronics.However,simultaneously satisfying these requirements poses a significant scientific challe...Polymer matrix composites with high dielectric constants and low dielectric losses are in high demand for flexible electronics.However,simultaneously satisfying these requirements poses a significant scientific challenge owing to the intrinsic trade-off relationship.Herein,we utilized the in situ controllable reduction of graphene oxide(GO)within a poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene)(P(VDF-Tr FE-CFE))matrix to regulate the dielectric properties.The as-obtained composite exhibited a high relative dielectric constant of 1415coupled with a low loss tangent of 0.380 at 100 Hz.Experimental and theoretical studies indicate that the increased degree of electron conjugation and conductivity of the reduced GO(RGO)are responsible for the high-k.The constrained reduction degree of GO,combined with its homogeneous dispersion in the polymer matrix,effectively suppresses long-range charge carrier migration,thereby minimizing dielectric loss.This novel strategy could be successfully applied to both organic and aqueous systems.Furthermore,a high-performance flexible capacitive proximity sensor was exemplified by the optimization of both the dielectric layer and electrode pattern,exhibiting excellent sensitivity and stability.The fundamental mechanisms elucidated in this study provide crucial design principles for developing dielectric PMCs with tailored properties,thereby opening new avenues for advanced flexible electronic applications.展开更多
Technical breakthrough of composite polymer electrolyte(CPE)is one of the key factors that determines the commercial process of the current solid-state lithium battery.However,high interface impedance limits its elect...Technical breakthrough of composite polymer electrolyte(CPE)is one of the key factors that determines the commercial process of the current solid-state lithium battery.However,high interface impedance limits its electrochemical performances.It is crucial to optimize the design of multiphase interfaces among different components in CPE for regulating Li+transport.Herein,a multi-affinity self-assembled 12-crown-4-TFSI(12C4-TFSI)supramolecular nanolayer is introduced into poly(vinylidene difluoride)-Li_(6.75)La_(3)Zr_(1.75)Ta_(0.25)O_(12)(PVDF-LLZTO)CPE as interface modifier.As a result,enhanced Li+conductivity of 4.29×10^(-4)S·cm^(-1),Li+transfer number of 0.44,and stable electrochemical window voltage of 4.8 V vs.Li/Li+at 30℃ are obtained.The symmetric Li||Li cell exhibits an improved critical current density(CCD)of 1.2 mA·cm^(-2) and steady cycling at 0.2 mA·cm^(-2) for over 850 h without visible voltage fluctuation.The assembled LiǁLiFePO4 coin solid-state cell delivers a high initial discharge capacity of 172.9 mAh·g^(-1) at 0.1 C,rate capability(up to 5.0 C)and outstanding cycling stability with a capacity retention of 87.2% after over 750 cycles at 1.0 C.The associated LiǁLiFePO4 pouch cell presents an initial specific discharge capacity of 112.3 mAh·g−1 and successfully runs 30 cycles with a final capacity of 101.8 mAh·g^(-1).This work offers a facile strategy to optimize multiphase interfaces of PVDF-LLZTO CPE for stable solid-state lithium battery.展开更多
Poly(vinylidene fluoride)(PVDF)-based solid polymer electrolytes(SPEs)with“lithium salt in polymer”configurations typically exhibit poor lithium salt dissociation and mechanical strength.In this study,we proposed a ...Poly(vinylidene fluoride)(PVDF)-based solid polymer electrolytes(SPEs)with“lithium salt in polymer”configurations typically exhibit poor lithium salt dissociation and mechanical strength.In this study,we proposed a composite polymer electrolyte(CPE)for solid-state lithium-ion batteries(LIBs)as a novel approach to address the challenges.The CPE incorporates a high dielectric polymer poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene)(P(VDF-TrFE-CTFE))as the polymer matrix,and sodium super ionic conductor(NASICON)-type ceramic Li_(1.5)Al_(0.5)Ti_(1.5)(PO_(4))_(3)(LATP)as fillers.The optimized CPE demonstrates enhanced dissociation of lithium salts,leading to high ionic conductivity tLi+(1.1 mS·cm^(-1))and improved lithium transference numbers(=0.51).Meanwhile,the interaction between LATP inorganic filler and P(VDF-TrFE-CTFE)enhances the elasticity and tensile strength(1.09 MPa)of the CPE.The graphite|CPE|NCM811(NCM stands for lithium nickel manganese cobalt oxide.Chemical formula of NCM811 is“LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)”)cell achieves a high specific capacity of 160 mAh·g^(-1) with excellent cycles stably for 300 cycles at 1 C.In addition,the flexible graphite|CPE|NCM811 pouch cell demonstrates exceptional capacity stability under dynamic bending for 10,000 times.Furthermore,the CPE can fulfil the fabrication process needs of flexible stacking-type and winding-type cells,highlighting its versatility and suitability for various LIB configurations in real applications.展开更多
With the merits of both solid polymer electrolytes(SPEs)and inorganic ceramic electrolytes(ICEs),composite polymer electrolytes(CPEs)prepared by coupling polymer matrix with inorganicfillers are broadly utilized in so...With the merits of both solid polymer electrolytes(SPEs)and inorganic ceramic electrolytes(ICEs),composite polymer electrolytes(CPEs)prepared by coupling polymer matrix with inorganicfillers are broadly utilized in solid lithium metal batteries(SLMBs).However,CPEs fabricated by a singlefiller with polymer matrix often exhibit unsatisfactory performance.Here,prepared by coupling poly(ethylene oxide)(PEO)matrix with a natural additive carboxymethyl cellulose lithium(CMC-Li)and an inorganicfiller mineral hectorite(Ht),an efficient CPE is reported.Detailedly,CMC-Li is considered to act as a“bridge”,which connects the Ht nanosheets distributed in PEO,thus establishing continuous Li^(+)transmission channels.Ht with a nanolayers structure vividly acts as“bricks”,pave the way for ion transference.In addition,oxygen atoms in CMC-Li contribute to adequately dissociating lithium salts,hydrogen bonding generated by hydroxyl groups is propitious to anchor anions to increase the Liþtransference number.Under the synergistic effect brought by CMC-Li and Ht,the electrolyte membrane PEO-10%Ht-4%CMC-Li(PHCL,in mass fraction)displays a high Liþtransfer number(0.73)and exceptional Li^(+)conductivity at 25℃(2.5×10^(-4)S/cm).Our work demonstrates a powerful mean to fabricate the efficient electrolyte membrane for SLMBs.展开更多
Power cables are important pieces of equipment for energy transmission,but achieving a good balance between flame retardancy and mechanical properties of cable sheaths remains a challenge.In this work,a novel intumesc...Power cables are important pieces of equipment for energy transmission,but achieving a good balance between flame retardancy and mechanical properties of cable sheaths remains a challenge.In this work,a novel intumescent flame retardant(IFR)system containing silicone-containing macromolecular charring agent(Si-MCA)and ammonium polyphosphate(APP)was designed to synergistically improve the flame retardancy and mechanical properties of ethylene-butyl acrylate copolymer(EBA)composites.The optimal mass ratio of APP/Si-MCA was 3/1 in EBA composites(EBA/APP-Si-31),corresponding to the best flame retardancy with 31.2% of limited oxygen index(LOI),V-0 rating in UL-94 vertical burning test,and 76.4%reduction on the peak of heat release rate(PHRR)in cone calorimeter test.The enhancement mechanism was attributed to the synergistic effect of APP/Si-MCA during combustion,including the radical-trapping effect,the dilution effect of non-flammable gases,and the barrier effect of the intumescent char layer.Meanwhile,the tensile results indicated that EBA/APP-Si-31 also exhibited good mechanical properties with the addition of maleic anhydride-grafted polyethylene(PE-g-MA)as the compatibilizer.Thus,the APP/Si-MCA combination is an effective IFRs system for preparing high-performance EBA composites,and it will promote their applications as cable sheath materials.展开更多
Self-healing(SH)polymer composites are a transformative achievement in polymer material technology that offers significant potential to extend the lifespan and reliability of materials.This work presents a novel appro...Self-healing(SH)polymer composites are a transformative achievement in polymer material technology that offers significant potential to extend the lifespan and reliability of materials.This work presents a novel approach to developing a hybrid natural-synthetic reinforced polymer composite with SH behavior using urea-free,non-toxic,environment-friendly material encapsulating resin,and hardener within a multicavity microcapsule(MC).This MC offers multiple healing because of its multicavity structure.These Xerogel MCs are integrated into hybrid bamboo/recycled glass fiber reinforced epoxy composite(25 wt% and 40 wt%)and were evaluated for their flexural strength,healing efficiency,moisture absorption,and thermal behavior.The results demonstrated that the composite containing 40 wt% exhibited the highest initial flexural strength and modulus retention after multiple healing cycles,approaching 80.67% and 61.34% respectively at 1st and 2nd cycles of healing efficiency.The behavior of self-healing hybrid composites(SHHC)in different environmental conditions was also investigated.Thermal Analysis TGA and DTA done on hybrid and other SH composites.Scanning electron microscopy shows the surface morphology of Xerogel MCs before and after damage,composite fractured surface,and how Healing Agent(HA)gets released and acquires surface after fracture.To ensure functional groups and chemical reactions between each component of the composite,FTIR analysis confirmed the successful encapsulation of HA inside MC.展开更多
The increasing power density of chips poses a significant challenge in the form of material aging for aluminumfilled polydimethylsiloxane(Al/PDMS)composites,which are widely used in thermal interface materials.Despite...The increasing power density of chips poses a significant challenge in the form of material aging for aluminumfilled polydimethylsiloxane(Al/PDMS)composites,which are widely used in thermal interface materials.Despite the growing importance of this issue,the specific mechanisms behind the interfacial aging process remain elusive,hindering a comprehensive grasp of the aging dynamics in these composites.In our research,we have developed an in-situ Raman aging monitoring system that leverages the non-contact and high-resolution capabilities of Raman spectroscopy to study the interface aging process.Our findings indicate a notable decrease in the intensity of the Raman peak as further cross-linking of the molecules during aging,with the most pronounced decline occurring at the interface between aluminum and PDMS.This insight could potentially elucidate why the interface in composite materials is frequently the site of failure during aging.Our study offers a versatile methodology for investigating the interfacial aging of polymer composites,contributing to a broader understanding of the interface behavior in composite materials at the molecular level.展开更多
基金the funding support from the National Key Research and Development Program of China(Grant Number 2021YFB2400300)National Natural Science Foundation of China(Grant Number 21875195,22021001)Fundamental Research Funds for the Central Universities(Grant Number 20720190040)。
文摘With excellent energy densities and highly safe performance,solidstate lithium batteries(SSLBs)have been hailed as promising energy storage devices.Solid-state electrolyte is the core component of SSLBs and plays an essential role in the safety and electrochemical performance of the cells.Composite polymer electrolytes(CPEs)are considered as one of the most promising candidates among all solid-state electrolytes due to their excellent comprehensive performance.In this review,we briefly introduce the components of CPEs,such as the polymer matrix and the species of fillers,as well as the integration of fillers in the polymers.In particular,we focus on the two major obstacles that affect the development of CPEs:the low ionic conductivity of the electrolyte and high interfacial impedance.We provide insight into the factors influencing ionic conductivity,in terms of macroscopic and microscopic aspects,including the aggregated structure of the polymer,ion migration rate and carrier concentration.In addition,we also discuss the electrode-electrolyte interface and summarize methods for improving this interface.It is expected that this review will provide feasible solutions for modifying CPEs through further understanding of the ion conduction mechanism in CPEs and for improving the compatibility of the electrode-electrolyte interface.
基金financially supported by Zhejiang Provincial Natural Science Foundation of China (No. LR20E020002)the National Natural Science Foundation of China (Nos.U20A20253 and 21972127)
文摘Substituting liquid electrolytes with solid elec-trolytes is considered as an important strategy to solve the problem of flammability and explosion for traditional lithium-ion batteries(LIB).However,neither inorganic solid electrolytes(ISE)nor solid polymer electrolytes(SPE)alone can meet the operating requirements for room-temperature(RT)all-solid-state lithium metal batteries(ASSLMB).Here,we report a three-dimensional(3D)nanofiber framework reinforced polyethylene oxide(PEO)-based composite polymer electrolytes(CPE)through con-structing a nanofiber framework combining polyacryloni-trile(PAN)and fast Li-ion conductor Li_(0.33)La_(0.557)TiO_(3)(LLTO)framework by electrospinning method.Mean-while,the PEO electrolyte filled in the pores of the PAN/LLTO nanofiber framework can effectively isolate the direct contact between the chemically active Ti^(4+)in LLTO with lithium metal,thereby avoiding the occurrence of interfacial reactions.Enhanced electrochemical stability makes a wide electrochemical window up to 4.8 V with an ionic conductivity of about 9.87×10^(-5)S·cm^(-1)at RT.Benefiting from the excellent lithium dendrite growth inhibition ability of 3D PAN/LLTO nanofiber framework,especially when the mass of LLTO reaches twice that of the PAN,Li/Li symmetric cell could cycle stably for 1000 h without a short circuit.In addition,under 30℃,the LiFePO_(4)/Li ASSLMB using such CPE delivers large capacities of 156.2 and 140 mAh·g^(-1)at 0.2C and 0.5C,respectively.These results provide a new insight for the development of the next generation of safe,high-perfor-mance ASSLMBs.
基金Project supported by Major Provincial Science and Technology Programs of Hunan (2011FJ1005)Central College on the 2010 Operational Costs of Basic Research Project (2010QZZD0101)
文摘Nano-La2O3 was modified with the vinyltrimethoxylsilane by hydrolysis and a novel poly （vinylidene fluoride-co-hexafluoropropylene） （PVDF-HFP） based composite polymer electrolyte doped with the modified nano-La2O3 was prepared by phase inversion method. The physicochemical properties were studied by SEM, FT-IR, XRD, TG and electrochemical methods. The results of FT-IR indicated that the nano-La2O3 was successfully modified with vinyltrimethoxylsilane. The XRD analysis showed that the incorporation of modified nano-La2O3 into the polymer electrolyte membranes could effectively reduce the crystallinity of PVDF-HFP, and the characterizations also suggested that thermal stability and electrochemical stability window could reach to 382°C and 5.1V, respectively; the reciprocal temperature dependence of ionic conductivity followed Vogel-Tamman-Fulcher （VTF） relation, ionic conductivity at room temperature was up to 3.5×10-3S/cm and lithium ions transference number was up to 0.42; the interfacial resistance increased at initial value about353Ω/cm2 and reached a steady value about 559Ω/cm2 after 5d storage at 30°C. The fabricated Li/As-prepared electrolytes/LiCoO2 coin cell showed excellent rate and cycle performances.
文摘(PEO)8LiClO4-SiO2 composite polymer electrolytes(CPEs)were prepared by in-situ reaction,in which ethyl-orthosilicate(TEOS)was catalyzed by HCl and NH3.H2O,respectively.The ionic conductivity,the contact angle and the morphology of inorganic particles in the CPEs were investigated by AC impedance spectra,contact angle method and TEM.The conductivities of acid-catalyzed CPE and alkali-catalyzed CPE are 2.2×10-5and 1.1×10-5S/cm respectively at 30℃.The results imply that the catalyst plays an important role in the structure of in-situ preparation of SiO2,and influences the surface energy and conductivity of CPE films directly.Meanwhile,the ionic conductivity is related to the surface energy.
基金supported by the State Key Laboratory of Catalytic Materials and Reaction Engineering(RIPP,SINOPEC)the National Natural Science Foundation of China(Nos.21878216,22005215)+1 种基金Hebei Province Innovation Ability Promotion Project(No.20312201D)the National Key Research and Development Program of China(No.2019YFE0118800)。
文摘The lithiated covalent organic framework(named TpPa-SO_(3) Li),which was prepared by a mild chemical lithiation strategy,was introduced in poly(ethylene oxide)(PEO)to produce the composite polymer electrolytes(CPEs).Li-ion can transfer along the PEO chain or across the layer of TpPa-SO_(3) Li within the nanochannels,resulting in a high Li-ion conductivity of3.01×10^(-4)S/cm at 60℃.When the CPE with 0.75 wt.%TpPa-SO_(3) Li was used in the LiFePO_(4)‖Li solid-state battery,the cell delivered a stable capacity of 125 mA·h/g after 250 cycles at 0.5 C,60℃.In comparison,the cell using the CPE without TpPa-SO_(3) Li exhibited a capacity of only 118 mA·h/g.
基金This work was supported by the National Natural Science Foundation of China (51973157,61904123)the Tianjin Natural Science Foundation (18JCQNJC02900)+3 种基金the Special Grade of the Financial Support from the China Postdoctoral Science Foundation (2020T130469)the Sci-ence and Technology Plans of Tianjin (19PTSYJC00010)the Science&Technol-ogy Development Fund of Tianjin Education Commission for Higher Education (2018KJ196)State Key Laboratory of Membrane and Membrane Separation,Tiangong University.
文摘Low-cost and flexible solid polymer electrolytes are promising in all-solid-state Li-metal batteries with high energy density and safety.However,both the low room-temperature ionic conductivities and the small Li^(+)transference number of these electrolytes significantly increase the internal resistance and overpotential of the battery.Here,we introduce Gd-doped CeO_(2) nanowires with large surface area and rich surface oxygen vacancies to the polymer electrolyte to increase the interaction between Gd-doped CeO_(2) nanowires and polymer electrolytes,which promotes the Li-salt dissociation and increases the concentration of mobile Li ions in the composite polymer electrolytes.The optimized composite polymer electrolyte has a high Li-ion conductivity of 5×10^(-4)4 S cm^(-1) at 30℃ and a large Li+transference number of 0.47.Moreover,the composite polymer electrolytes have excellent compatibility with the metallic lithium anode and high-voltage LiNi_(0.8)Mn _(0.1)Co_(0.1)O_(2)(NMC)cathode,providing the stable cycling of all-solid-state batteries at high current densities.
文摘PEO-LiClO4-TiO2 composite polymer electrolyte films were prepared. TiO2 was formed directly in matrix by hydrolysis and condensation reaction of tetrabutyl titanate. The crystallinity, morphology and ionic conductivity of composite polymer electrolyte films were examined by differential scanning calorimetry, scanning electron microscopy, atom force microscopy and alternating current impedance spectroscopy, respectively. The glass transition temperature and the crystallinity of composite polymer electrolytes are decreased compared with those of PEO-LiClO4 polymer electrolyte film. The results show that TiO2 particles are uniformly dispersed in PEO-LiClO4-5%TiO2 composite polymer electrolyte film. The maximal conductivity of 5.5×10、5 Scm at 20 ℃ of PEO-LiClO4-TiO2 film is obtained at 5% mass fraction of TiO2.
基金Project (No. 71-088/2007) supported by Program "Partnerships in Priority Areas", the Romanian Ministry of Education and Research
文摘We present an empirical model for the effective thermal conductivity (ETC) of a polymer composite that includes dependency on the filler size distribution-chosen as the Rosin-Rammler distribution. The ETC is determined based on certain hypotheses that connect the behavior of a real composite material A, to that of a model composite material B, filled with mono-dimensional filler. The application of these hypotheses to the Maxwell model for ETC is presented. The validation of the new model and its characteristic equation was carried out using experimental data from the reference. The comparison showed that by using the size distribution law a very good fit between the equation of the new model (the size distribution model for the ETC) and the reference experimental results is obtained, even for high volume fractions, up to about 50%.
基金Project(2011FJ1005)supported by the Major Provincial Science and Technology Program of Hunan Province,ChinaProject(2010qzzd0101)supported by the Central College on the 2010 Operational Costs of Basic Research Program,China
文摘Poly（vinylidene fluoride-co-hexafluoropropylene） （PVDF-HFP） based composite polymer electrolyte （CPE） modified with CeO2, La2O3 and Y2O3 nano-rare earth oxides was prepared by phase inversion technique. Physical and chemical properties of the modified CPEs were studied by SEM, TG-DSC and electrochemical methods. The results show that the CPE modified with 10% La2O3 （mass fraction） has the best practical applicability, which indicates that the thermal and electrochemical stability can reach over 400 ℃ and 4.5 V, respectively, and temperature dependence of ionic conductivity follows Vogel-Tamman-Fulcher （VTF） relationship and ionic conductivity at room temperature is up to 3.3 mS/cm. The interfacial resistance Ri reaches a stable value about 557 Ω after 6 d storage.
基金financially supported by the National 863 Program(No.2011AA11A235)the National Key Program for Basic Research of China(No.2009CB220100)Basic Research Fund of Beijing Institute of Technology(No.3100012211111 )
文摘Composite polymer electrolytes based on poly（ethylene oxide）-polysiloxane/l-butyl-3-methylimida- zolium bis（trifluoromethanesulfonyl）imide/organomontmorillonite （PEO-PDMS/IL/OMMT） were pre- pared and characterized. Addition of both an ionic liquid and OMMT to the polymer base of PEO-PDMS resulted in an increase in ionic conductivity. At room temperature, the ionic conductivity of sample PPB 100-OMMT4 was 2.19 × 10-3 S/cm. The composite polymer electrolyte also exhibited high thermal and electrochemical stability and may potentially be applied in lithium batteries.
文摘To analyze the feasibility of application of composite material as the insulating material, it is necessary to have knowledge of some of its mechanical properties. An insulating material may suffer from the most different efforts, but the major applications suggest mechanical bending and compression tests because the insulation can be applied on roofs of homes, liners similar to, in the form of plates. Thus, the product is continually flexed. When the material is used on a floor, it suffers constant compressions over its use. For tests performed in this study, we used the ASTM D695-96 for compression, an example of literature. Using such a standard test, specimens were produced for compression test, with specimens made of cylindrical shapes, respecting the condition that the height of the specimen corresponds to twice the diameter of the base. Polyurethane castor without charge vermiculite and mass loads of 10%, 15% and 20% matrix： four specimens for each type of material were produced. The composites were tested in a universal testing machine at a speed of 2 mm/s. The results are average values of four test samples, and initially show the behavior of castor oil polyurethane during the compression test, which is detailed in the stress versus strain curve. The achieved results are promising, and detailed in this paper.
基金supported by the National Natural Science Foundation of China (Nos.52203066,51973157,61904123)the Tianjin Natural Science Foundation (No.18JCQNJC02900)+3 种基金National Innovation and Entrepreneurship Training Program for College students (No.202310058007)Tianjin Municipal College Students’ Innovation and Entrepreneurship Training Program (No.202310058088)Science & Technology Development Fund of Tianjin Education Commission for Higher Education (No.2018KJ196)State Key Laboratory of Membrane and Membrane Separation,Tiangong University
文摘Satisfactory ionic conductivity,excellent mechanical stability,and high-temperature resistance are the prerequisites for the safe application of solid polymer electrolytes(SPEs)in all-solid-state lithium metal batteries(ASSLMBs).In this study,a novel poly(m-phenylene isophthalamide)(PMIA)-core/poly(ethylene oxide)(PEO)-shell nanofiber membrane and the functional Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)ceramic nanopar-ticle are simultaneously introduced into the PEO-based SPEs to prepare composite polymer electrolytes(CPEs).The core PMIA layer of composite nanofibers can greatly improve the mechanical strength and thermal stability of the CPEs,while the shell PEO layer can provide the 3D continuous transport channels for lithium ions.In addition,the introduction of functional LLZTO nanoparticle not only reduces the crys-tallinity of PEO,but also promotes the dissociation of lithium salts and releases more Li^(+)ions through its interaction with the Lewis acid-base of anions,thereby overall improving the transport of lithium ions.Consequently,the optimized CPEs present high ionic conductivity of 1.38×10^(−4)S/cm at 30℃,signifi-cantly improved mechanical strength(8.5 MPa),remarkable thermal stability(without obvious shrinkage at 150℃),and conspicuous Li dendrites blocking ability(>1800 h).The CPEs also both have good com-patibility and cyclic stability with LiFePO_(4)(>2000 cycles)and high-voltage LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NMC811)(>500 cycles)cathodes.In addition,even at low temperature(40℃),the assembled LiFePO4/CPEs/Li bat-tery still can cycle stably.The novel design can provide an effective way to exploit high-performance solid-state electrolytes.
文摘A novel composite polymer electrolyte was prepared by blending an appropriateamount of LiClO_4 and 10 percent (mass fraction) fumed SiO_2 with the block copolymer of poly(ethylene oxide) (PEO) synthesized by poly (ethylene glycol) (PEG) 400 and CH_2C1_2 The ionicconductivity, electrochemical stability, interfacial characteristic and thermal behavior of thecomposite polymer electrolyte were studied by the measurements of AC impedance spectroscopy, linearsweep voltammetry and differential scanning calorimetry (DSC), respectively. The glass transitiontemperature acts as a function of salt concentration, which increases with the LiClO_4 content.Lewis acid-base model interaction mechanism was introduced to interpret the interactive relationbetween the filled fumed SiO_2 and the lithium salt in the composite polymer electrolyte. Over thesalt concentration range and the measured temperature, the maximum ionic conductivity of thecomposite polymer electrolyte (10^(-4.41) S/cm) appeared at EO/Li=25 (mole ratio) and 30 deg C, andthe beginning oxidative degradation potential versus Li beyond 5 V.
基金financially supported by the Innovation and Technology Commission of the Hong Kong SAR Government(No.MRP/020/21)Hong Kong Polytechnic University(No.847A)+1 种基金RI-Wear Seed Fund of Poly U(1-CD8J)Start-up Fund of Poly U(1-BD49)。
文摘Polymer matrix composites with high dielectric constants and low dielectric losses are in high demand for flexible electronics.However,simultaneously satisfying these requirements poses a significant scientific challenge owing to the intrinsic trade-off relationship.Herein,we utilized the in situ controllable reduction of graphene oxide(GO)within a poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene)(P(VDF-Tr FE-CFE))matrix to regulate the dielectric properties.The as-obtained composite exhibited a high relative dielectric constant of 1415coupled with a low loss tangent of 0.380 at 100 Hz.Experimental and theoretical studies indicate that the increased degree of electron conjugation and conductivity of the reduced GO(RGO)are responsible for the high-k.The constrained reduction degree of GO,combined with its homogeneous dispersion in the polymer matrix,effectively suppresses long-range charge carrier migration,thereby minimizing dielectric loss.This novel strategy could be successfully applied to both organic and aqueous systems.Furthermore,a high-performance flexible capacitive proximity sensor was exemplified by the optimization of both the dielectric layer and electrode pattern,exhibiting excellent sensitivity and stability.The fundamental mechanisms elucidated in this study provide crucial design principles for developing dielectric PMCs with tailored properties,thereby opening new avenues for advanced flexible electronic applications.
基金We gratefully acknowledge the financial support of the National Key Research and Development Program of China(No.2021YFE0107200)the National Natural Science Foundation of China(No.21773167)the Key R&D Project funded by Department of Science and Technology of Jiangsu Province(No.BE2020003).
文摘Technical breakthrough of composite polymer electrolyte(CPE)is one of the key factors that determines the commercial process of the current solid-state lithium battery.However,high interface impedance limits its electrochemical performances.It is crucial to optimize the design of multiphase interfaces among different components in CPE for regulating Li+transport.Herein,a multi-affinity self-assembled 12-crown-4-TFSI(12C4-TFSI)supramolecular nanolayer is introduced into poly(vinylidene difluoride)-Li_(6.75)La_(3)Zr_(1.75)Ta_(0.25)O_(12)(PVDF-LLZTO)CPE as interface modifier.As a result,enhanced Li+conductivity of 4.29×10^(-4)S·cm^(-1),Li+transfer number of 0.44,and stable electrochemical window voltage of 4.8 V vs.Li/Li+at 30℃ are obtained.The symmetric Li||Li cell exhibits an improved critical current density(CCD)of 1.2 mA·cm^(-2) and steady cycling at 0.2 mA·cm^(-2) for over 850 h without visible voltage fluctuation.The assembled LiǁLiFePO4 coin solid-state cell delivers a high initial discharge capacity of 172.9 mAh·g^(-1) at 0.1 C,rate capability(up to 5.0 C)and outstanding cycling stability with a capacity retention of 87.2% after over 750 cycles at 1.0 C.The associated LiǁLiFePO4 pouch cell presents an initial specific discharge capacity of 112.3 mAh·g−1 and successfully runs 30 cycles with a final capacity of 101.8 mAh·g^(-1).This work offers a facile strategy to optimize multiphase interfaces of PVDF-LLZTO CPE for stable solid-state lithium battery.
文摘Poly(vinylidene fluoride)(PVDF)-based solid polymer electrolytes(SPEs)with“lithium salt in polymer”configurations typically exhibit poor lithium salt dissociation and mechanical strength.In this study,we proposed a composite polymer electrolyte(CPE)for solid-state lithium-ion batteries(LIBs)as a novel approach to address the challenges.The CPE incorporates a high dielectric polymer poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene)(P(VDF-TrFE-CTFE))as the polymer matrix,and sodium super ionic conductor(NASICON)-type ceramic Li_(1.5)Al_(0.5)Ti_(1.5)(PO_(4))_(3)(LATP)as fillers.The optimized CPE demonstrates enhanced dissociation of lithium salts,leading to high ionic conductivity tLi+(1.1 mS·cm^(-1))and improved lithium transference numbers(=0.51).Meanwhile,the interaction between LATP inorganic filler and P(VDF-TrFE-CTFE)enhances the elasticity and tensile strength(1.09 MPa)of the CPE.The graphite|CPE|NCM811(NCM stands for lithium nickel manganese cobalt oxide.Chemical formula of NCM811 is“LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)”)cell achieves a high specific capacity of 160 mAh·g^(-1) with excellent cycles stably for 300 cycles at 1 C.In addition,the flexible graphite|CPE|NCM811 pouch cell demonstrates exceptional capacity stability under dynamic bending for 10,000 times.Furthermore,the CPE can fulfil the fabrication process needs of flexible stacking-type and winding-type cells,highlighting its versatility and suitability for various LIB configurations in real applications.
基金the National Natural Science Foundation of China(22205147)Natural Science Foundation of Qinghai Province(2024-ZJ-952)Youth Innovation Promotion Association of the Chinese Academy of Sciences.
文摘With the merits of both solid polymer electrolytes(SPEs)and inorganic ceramic electrolytes(ICEs),composite polymer electrolytes(CPEs)prepared by coupling polymer matrix with inorganicfillers are broadly utilized in solid lithium metal batteries(SLMBs).However,CPEs fabricated by a singlefiller with polymer matrix often exhibit unsatisfactory performance.Here,prepared by coupling poly(ethylene oxide)(PEO)matrix with a natural additive carboxymethyl cellulose lithium(CMC-Li)and an inorganicfiller mineral hectorite(Ht),an efficient CPE is reported.Detailedly,CMC-Li is considered to act as a“bridge”,which connects the Ht nanosheets distributed in PEO,thus establishing continuous Li^(+)transmission channels.Ht with a nanolayers structure vividly acts as“bricks”,pave the way for ion transference.In addition,oxygen atoms in CMC-Li contribute to adequately dissociating lithium salts,hydrogen bonding generated by hydroxyl groups is propitious to anchor anions to increase the Liþtransference number.Under the synergistic effect brought by CMC-Li and Ht,the electrolyte membrane PEO-10%Ht-4%CMC-Li(PHCL,in mass fraction)displays a high Liþtransfer number(0.73)and exceptional Li^(+)conductivity at 25℃(2.5×10^(-4)S/cm).Our work demonstrates a powerful mean to fabricate the efficient electrolyte membrane for SLMBs.
基金supported by the National Natural Science Foundation of China(52473059)Taishan Scholar Constructive Engineering Foundation of Shandong Province(tsqn202103079)Key Research and Development Plan of Shandong Province(2024TSGC0264).
文摘Power cables are important pieces of equipment for energy transmission,but achieving a good balance between flame retardancy and mechanical properties of cable sheaths remains a challenge.In this work,a novel intumescent flame retardant(IFR)system containing silicone-containing macromolecular charring agent(Si-MCA)and ammonium polyphosphate(APP)was designed to synergistically improve the flame retardancy and mechanical properties of ethylene-butyl acrylate copolymer(EBA)composites.The optimal mass ratio of APP/Si-MCA was 3/1 in EBA composites(EBA/APP-Si-31),corresponding to the best flame retardancy with 31.2% of limited oxygen index(LOI),V-0 rating in UL-94 vertical burning test,and 76.4%reduction on the peak of heat release rate(PHRR)in cone calorimeter test.The enhancement mechanism was attributed to the synergistic effect of APP/Si-MCA during combustion,including the radical-trapping effect,the dilution effect of non-flammable gases,and the barrier effect of the intumescent char layer.Meanwhile,the tensile results indicated that EBA/APP-Si-31 also exhibited good mechanical properties with the addition of maleic anhydride-grafted polyethylene(PE-g-MA)as the compatibilizer.Thus,the APP/Si-MCA combination is an effective IFRs system for preparing high-performance EBA composites,and it will promote their applications as cable sheath materials.
文摘Self-healing(SH)polymer composites are a transformative achievement in polymer material technology that offers significant potential to extend the lifespan and reliability of materials.This work presents a novel approach to developing a hybrid natural-synthetic reinforced polymer composite with SH behavior using urea-free,non-toxic,environment-friendly material encapsulating resin,and hardener within a multicavity microcapsule(MC).This MC offers multiple healing because of its multicavity structure.These Xerogel MCs are integrated into hybrid bamboo/recycled glass fiber reinforced epoxy composite(25 wt% and 40 wt%)and were evaluated for their flexural strength,healing efficiency,moisture absorption,and thermal behavior.The results demonstrated that the composite containing 40 wt% exhibited the highest initial flexural strength and modulus retention after multiple healing cycles,approaching 80.67% and 61.34% respectively at 1st and 2nd cycles of healing efficiency.The behavior of self-healing hybrid composites(SHHC)in different environmental conditions was also investigated.Thermal Analysis TGA and DTA done on hybrid and other SH composites.Scanning electron microscopy shows the surface morphology of Xerogel MCs before and after damage,composite fractured surface,and how Healing Agent(HA)gets released and acquires surface after fracture.To ensure functional groups and chemical reactions between each component of the composite,FTIR analysis confirmed the successful encapsulation of HA inside MC.
基金supported by the National Natural Science Foundation of China(No.52303092)Talent Recruitment Project of Guangdong Province(No.2023QN10X078)+2 种基金Open Project of Yunnan Precious Metals Laboratory Co.,Ltd(No.YPML-2023050278)National Key R&D Project from Ministry of Science and Technology of China(No.2022YFA1203100)Shenzhen Science and Technology Research Funding(No.JCYJ20200109114401708)。
文摘The increasing power density of chips poses a significant challenge in the form of material aging for aluminumfilled polydimethylsiloxane(Al/PDMS)composites,which are widely used in thermal interface materials.Despite the growing importance of this issue,the specific mechanisms behind the interfacial aging process remain elusive,hindering a comprehensive grasp of the aging dynamics in these composites.In our research,we have developed an in-situ Raman aging monitoring system that leverages the non-contact and high-resolution capabilities of Raman spectroscopy to study the interface aging process.Our findings indicate a notable decrease in the intensity of the Raman peak as further cross-linking of the molecules during aging,with the most pronounced decline occurring at the interface between aluminum and PDMS.This insight could potentially elucidate why the interface in composite materials is frequently the site of failure during aging.Our study offers a versatile methodology for investigating the interfacial aging of polymer composites,contributing to a broader understanding of the interface behavior in composite materials at the molecular level.
