Design process of A/ADm-BCn type directional eutectic composites was instanced by investigating Al-Mg-Si-Li and Ni-Mo-C-Al systems in this study by thermoanalysis and directional solidification techniques. It was demo...Design process of A/ADm-BCn type directional eutectic composites was instanced by investigating Al-Mg-Si-Li and Ni-Mo-C-Al systems in this study by thermoanalysis and directional solidification techniques. It was demonstrated that A(D)-BCn eutectic alloys could be obtained more conveniently by using Smith′s thermoanalysis method to trace change of the eutectic Points of A-BCn induced by addition of components D. A/ADm-BCn directional eutectic composites could be produced from directionally solidified A/ADm-BCn alloys after proper heat treatments if components D have higher solid solubility in components A at high temperature and stable of metastable phases ADm could be formed at room temperature.展开更多
Microstructure control is a great challenge in the high-temperature gradient directional solidification of eutectic composite ceramics due to the complex solidification behavior.Herein,the microstructure trans-formati...Microstructure control is a great challenge in the high-temperature gradient directional solidification of eutectic composite ceramics due to the complex solidification behavior.Herein,the microstructure trans-formation of faceted Al_(2)O_(3)/Er_(3)Al_(5)O_(12) thermal emission eutectic composite ceramics is explored over wide ranges of compositions(13.5 mol%-22.5 mol%Er_(2)O_(3))and solidification rates(2-200μm/s).Entirely cou-pled eutectics with primary phases suppressed are fabricated and the coupled zone is broadened in a wide range of 15.5 mol%-22.5 mol%Er_(2)O_(3) at low solidification rates.The competitive growth between eutectic and dendrite is evaluated on the basis of the maximum interface temperature criterion.In ad-dition,the mechanisms of irregular eutectic spacing selection and adjustment under different solidifi-cation rates are revealed based on Magnin-Kurz model.A successful prediction of lamellar to rod-like eutectics is achieved associated with the dynamic instability of lamellar eutectic and the corresponding enlarged coexistence region is mapped based on the interface undercooling.According to the well mi-crostructure tailoring,the flexural strength of Al_(2)O_(3)/Er_(3)Al_(5)O_(12) eutectic composite ceramics has improved from 508 MPa up to 1800 MPa due to the refined eutectic spacing with low fluctuation.The eutectic composite ceramics show strong selective optical absorption and the intensity increases with the refin-ing microstructure.The as-designed Al_(2)O_(3)/Er_(3)Al_(5)O_(12) composites with microstructural tailoring have great potential as integrations of structural and functional materials.展开更多
This work mainly involved the preparation of a nano-scale form-stable phase change material(PCM) consisting of capric and myristic acid(CA-MA) binary eutectic acting as thermal absorbing material and nano silicon ...This work mainly involved the preparation of a nano-scale form-stable phase change material(PCM) consisting of capric and myristic acid(CA-MA) binary eutectic acting as thermal absorbing material and nano silicon dioxide(nano-SiO_2) serving as the supporting material. Industrial water glass for preparation of the nano silicon dioxide matrix and CA-MA eutectic mixture were compounded by single-step sol-gel method with the silane coupling agent. The morphology, chemical characterization and form stability property of the composite PCM were investigated by transmission electron microscopy(TEM), scanning electron microscopy(SEM), Fourier-transform infrared(FT-IR) spectroscopy and polarizing microscopy(POM). It was indicated that the average diameter of the composite PCM particle ranged from 30-100 nm. The CA-MA eutectic was immobilized in the network pores constructed by the Si-O bonds so that the composite PCM was allowed no liquid leakage above the melting temperature of the CA-MA eutectic. Differential scanning calorimetry(DSC) and thermogravimetric analysis(TGA) measurement were conducted to investigate the thermal properties and stability of the composite PCM. From the measurement results, the mass fraction of the CA-MA eutectic in the composite PCM was about 40%. The phase change temperature and latent heat of the composite were determined to be 21.15 ℃ and 55.67 J/g, respectively. Meanwhile, thermal conductivity of the composite was measured to be 0.208 W·m^(-1)·K^(-1) by using the transient hot-wire method. The composite PCM was able to maintain the surrounding temperature close to its phase change temperature and behaved well in thermalregulated performance which was verified by the heat storage-release experiment. This kind of form-stable PCM was supposed to complete thermal insulation even temperature regulation by the dual effect of relatively low thermal conductivity and phase change thermal storage-release properties. So it can be formulated that the nanoscale CA-MA/SiO_2 composite PCM with the form-stable property, good thermal storage capacity and relatively low thermal conductivity can be applied for energy conservation as a kind of thermal functional material.展开更多
In order to improve the thermal storage capacity of expanded vermiculite(EV) based formstable composite PCM(FS-PCM) via organic modification of EV, first, EV was modified with a sodium stearate(Na St) as surface...In order to improve the thermal storage capacity of expanded vermiculite(EV) based formstable composite PCM(FS-PCM) via organic modification of EV, first, EV was modified with a sodium stearate(Na St) as surface modifier, and organic EV(OEV) with hydrophobicity and higher adsorption capacity for fatty acid was obtained. A novel capric-stearic acid eutectic(CA-SA)/OEV FS-PCM with high thermal storage capacity was then developed. OEV and CA-SA/OEV were characterized by scanning electron microscopy(SEM), X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FTIR), differential scanning calorimetry(DSC), thermal gravimetry(TG), and thermal cycling test. Results showed that OEV has obvious hydrophobicity and a higher adsorption capacity for fatty acid. Its adsorption ratio has increased by 48.71% compared with that of EV. CA-SA/OEV possesses high thermal storage density(112.52 J/g), suitable melting temperature(20.49 ℃), good chemical compatibility, excellent thermal stability and reliability, indicating great application potential for building energy efficiency. Moreover, organic modification of inorganic matrix may offer novel options for improving its adsorption capacity for organic PCMs and increasing heat storage capacity of corresponding FS-PCMs.展开更多
CE (=%C+(1/3)x(%Si)) does not suit experiment results in many cases. In this work, the effect of alloy elements on primary crystal temperature was measured and the relationship between primary crystal temperatu...CE (=%C+(1/3)x(%Si)) does not suit experiment results in many cases. In this work, the effect of alloy elements on primary crystal temperature was measured and the relationship between primary crystal temperature (Tc) and carbon equivalent (CEL) was investigated. The results show that Tc (Celsius degree) = 1650-110 × (%C) -25 × (%Si)+3 × (%Mn) -35 × (%P) -71 × (%5)-2 × (%Ni) -7 × (%Cr); CEL=%C + 0.23×(%Si)-0.03× (%Mn)+0.32×(%P)+0.64×(%S) +0.02×(%Ni)+0.06×(%Cr). That is, in hypo eutectic composition, carbon equivalent should be calculated with CEL=%C+ 0.23×(%Si), not with CE=%C+(1/3) x(%Si).展开更多
Fe-Al-Ta eutectic composites were obtained by a modified Bridgman directional solidification technique at different solidification rates.Solidification microstructure transforms from regular eutectic to eutectic colon...Fe-Al-Ta eutectic composites were obtained by a modified Bridgman directional solidification technique at different solidification rates.Solidification microstructure transforms from regular eutectic to eutectic colony with the increase of the solidification rate.The solid/liquid interface of Fe-Al-Ta eutectic evolves from planar interface to cellular interface with the increase of the solidification rate.In addition,threepoint bending method was adopted to study the room-temperature fracture toughness of the as-cast Fe-Al-Ta eutectic alloy and the Fe-Al-Ta eutectic composites.Moreover,the fracture morphologies,the crack propagation path and the strengthening mechanism of Fe-Al-Ta eutectic were discussed.展开更多
In the present paper, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and X-ray diffraction (XRD) were used to examine the effects of a Sr-Y composite modifier on the microstructure ...In the present paper, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and X-ray diffraction (XRD) were used to examine the effects of a Sr-Y composite modifier on the microstructure of A356 alloy. After adding Y to A356, YAl 3 compounds formed, and the size of the α (Al) crystal nucleus increased. The degree of supercooling caused by Sr-Y composite modifier was higher than Sr modification by 2.7 °C, leading to an increased nucleation rate. This increase in supercooling temperature was favorable to the refinement of eutectic structure of the alloy and its eutectic reaction was delayed to the maximum extent. The Si phase in the as-cast Sr-Y composite-modified A356 alloy was either granular or flaky. No large flakes of eutectic Si were found, and the modification effects were completely comparable with those obtained using a lone Sr modifier. After T6 heat treatment, most of the eutectic Si showed a grain-like shape with smaller grains. No eutectic Si with long-strip shapes, significant enhancements in the particle roundness and evenness of the Si crystals, and increased globosity were observed. Both the roundness and evenness of the grained Si crystals were enhanced, and the amount of globular eutectic Si available increased, these findings showed that excellent modification effects were achieved.展开更多
In order to confirm the eutectic composition, eutectic temperature and phases of Al-rich Al-RE(La, Ce, Pr, Nd) binary systems, the eutectic Al-RE alloys with the controversial compositions were investigated. The sca...In order to confirm the eutectic composition, eutectic temperature and phases of Al-rich Al-RE(La, Ce, Pr, Nd) binary systems, the eutectic Al-RE alloys with the controversial compositions were investigated. The scanning electron microscopy/energy dispersive spectroscopy(SEM/EDS), differential scanning calorimetric(DSC) and cooling curve tests analysis indicated that a similar eutectic composition(~12 wt.% RE) on the Al-rich region was observed in the Al-La, Al-Ce, Al-Pr and Al-Nd alloys, and the eutectic structure of the alloys was consisted of α-Al and α-Al11RE3 phases by combining with X-ray diffraction(XRD) tests. In addition, the eutectic temperatures determined by DSC and cooling curve tests were very close and around 645 oC.展开更多
Although rare earth zirconates(RE_(2)Zr_(2)O_(7))have garnered attention as viable candidates for thermal barrier coatings(TBCs),they suffer from low fracture toughness and accelerated calcium–magnesium–alumina–sil...Although rare earth zirconates(RE_(2)Zr_(2)O_(7))have garnered attention as viable candidates for thermal barrier coatings(TBCs),they suffer from low fracture toughness and accelerated calcium–magnesium–alumina–silicate(CMAS)melt corrosion at high service temperatures,which impedes their practical application.In this work,we developed a series of REAlO_(3)/RE_(2)Zr_(2)O_(7)(RE=La,Nd,Sm,Eu,Gd,and Dy)composites with a eutectic composition that not only significantly enhanced the fracture toughness by more than 40%relative to that of RE_(2)Zr_(2)O_(7)but also exhibited improved resistance to CMAS corrosion.The increase in toughness arises from multiple mechanisms,such as ferroelastic toughening,fine-grain strengthening,and residual stress toughening,all of which trigger more crack defects and energy consumption.Additionally,the CMAS penetration depth of the REAlO_(3)/RE_(2)Zr_(2)O_(7)composites is approximately 36%lower than that of RE_(2)Zr_(2)O_(7).Al–O constituents in composites can capture CaO,SiO_(2),and MgO in CMAS melts and increase their viscosity,resulting in enhanced CMAS corrosion resistance.The thermophysical properties of the REAlO_(3)/RE_(2)Zr_(2)O_(7)composites were also investigated,and their coefficient of thermal expansion and thermal conductivity are comparable to those of 7–8 wt%Y_(2)O_(3)partially stabilized ZrO2(YSZ),indicating their potential as TBC materials.展开更多
Polymer-based solid electrolytes have been extensively studied for solid-state lithium metal batteries to achieve high energy density and reliable security.But,its practical application is severely limited by low ioni...Polymer-based solid electrolytes have been extensively studied for solid-state lithium metal batteries to achieve high energy density and reliable security.But,its practical application is severely limited by low ionic conductivity and slow Li+transference.Herein,based on the“binary electrolytes”of poly(vinylidene fluoride-chlorotrifluoroethylene)(P(VDF-CTFE))and lithium salt(LiTFSI),a kind of eutectogel hybrid electrolytes(EHEs)with high Li+transference number was developed via tuning the spontaneous coupling of charge and vacated space generated by Li-cation diffusion utilizing the Li6.4La3Zr1.4Ta0.6O12(LLZTO)dopant.LLZTO doping promotes the dissociation of lithium salt,increases Li+carrier density,and boosts ion jumping and the coordination/decoupling reactions of Li+.As a result,the optimized EHEs-10%possess a high Li-transference number of 0.86 and a high Li+conductivity of 3.2×10–4 S·cm–1 at room temperature.Moreover,the prepared EHEs-10%composite solid electrolyte presents excellent lithiumphilic and compatibility,and can be tested stably for 1,200 h at 0.3 mA·cm–2 with assembled lithium symmetric batteries.Likewise,the EHEs-10%films match well with high-loading LiFePO4 and LiCoO2 cathodes(>10 mg·cm–2)and exhibit remarkable interface stability.Particularly,the LiFePO4//EHEs-10%//Li and LiCoO2//EHEs-10%//Li cells deliver high rate performance of 118 mAh·g–1 at 1 C and 93.7 mAh·g–1 at 2 C with coulombic efficiency of 99.3%and 98.1%,respectively.This work provides an in-depth understanding and new insights into our design for polymer electrolytes with fast Li+diffusion.展开更多
文摘Design process of A/ADm-BCn type directional eutectic composites was instanced by investigating Al-Mg-Si-Li and Ni-Mo-C-Al systems in this study by thermoanalysis and directional solidification techniques. It was demonstrated that A(D)-BCn eutectic alloys could be obtained more conveniently by using Smith′s thermoanalysis method to trace change of the eutectic Points of A-BCn induced by addition of components D. A/ADm-BCn directional eutectic composites could be produced from directionally solidified A/ADm-BCn alloys after proper heat treatments if components D have higher solid solubility in components A at high temperature and stable of metastable phases ADm could be formed at room temperature.
基金supported by the National Natural Science Foundation of China (Nos.52130204,52174376,and 51822405)the Guangdong Basic and Applied Basic Research Foundation (No.2021B1515120028)+2 种基金the Science and Technology Innovation Team Plan of Shaan Xi Province (No.2021TD-17)the Youth Innovation Team of Shaanxi Universities,Fundamental Research Funds for the Central Universities (No.D5000210902)the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University (Nos.CX2021056,CX2021066,and CX2022033),China.
文摘Microstructure control is a great challenge in the high-temperature gradient directional solidification of eutectic composite ceramics due to the complex solidification behavior.Herein,the microstructure trans-formation of faceted Al_(2)O_(3)/Er_(3)Al_(5)O_(12) thermal emission eutectic composite ceramics is explored over wide ranges of compositions(13.5 mol%-22.5 mol%Er_(2)O_(3))and solidification rates(2-200μm/s).Entirely cou-pled eutectics with primary phases suppressed are fabricated and the coupled zone is broadened in a wide range of 15.5 mol%-22.5 mol%Er_(2)O_(3) at low solidification rates.The competitive growth between eutectic and dendrite is evaluated on the basis of the maximum interface temperature criterion.In ad-dition,the mechanisms of irregular eutectic spacing selection and adjustment under different solidifi-cation rates are revealed based on Magnin-Kurz model.A successful prediction of lamellar to rod-like eutectics is achieved associated with the dynamic instability of lamellar eutectic and the corresponding enlarged coexistence region is mapped based on the interface undercooling.According to the well mi-crostructure tailoring,the flexural strength of Al_(2)O_(3)/Er_(3)Al_(5)O_(12) eutectic composite ceramics has improved from 508 MPa up to 1800 MPa due to the refined eutectic spacing with low fluctuation.The eutectic composite ceramics show strong selective optical absorption and the intensity increases with the refin-ing microstructure.The as-designed Al_(2)O_(3)/Er_(3)Al_(5)O_(12) composites with microstructural tailoring have great potential as integrations of structural and functional materials.
基金Funded by the National Natural Science Foundation of China(No.51308275)Natural Science Foundation of Liaoning Province(No.SY2016004)the Colleges and Universities Excellent Talents Supporting Plan Program of Liaoning Province(No.LJQ2015049)
文摘This work mainly involved the preparation of a nano-scale form-stable phase change material(PCM) consisting of capric and myristic acid(CA-MA) binary eutectic acting as thermal absorbing material and nano silicon dioxide(nano-SiO_2) serving as the supporting material. Industrial water glass for preparation of the nano silicon dioxide matrix and CA-MA eutectic mixture were compounded by single-step sol-gel method with the silane coupling agent. The morphology, chemical characterization and form stability property of the composite PCM were investigated by transmission electron microscopy(TEM), scanning electron microscopy(SEM), Fourier-transform infrared(FT-IR) spectroscopy and polarizing microscopy(POM). It was indicated that the average diameter of the composite PCM particle ranged from 30-100 nm. The CA-MA eutectic was immobilized in the network pores constructed by the Si-O bonds so that the composite PCM was allowed no liquid leakage above the melting temperature of the CA-MA eutectic. Differential scanning calorimetry(DSC) and thermogravimetric analysis(TGA) measurement were conducted to investigate the thermal properties and stability of the composite PCM. From the measurement results, the mass fraction of the CA-MA eutectic in the composite PCM was about 40%. The phase change temperature and latent heat of the composite were determined to be 21.15 ℃ and 55.67 J/g, respectively. Meanwhile, thermal conductivity of the composite was measured to be 0.208 W·m^(-1)·K^(-1) by using the transient hot-wire method. The composite PCM was able to maintain the surrounding temperature close to its phase change temperature and behaved well in thermalregulated performance which was verified by the heat storage-release experiment. This kind of form-stable PCM was supposed to complete thermal insulation even temperature regulation by the dual effect of relatively low thermal conductivity and phase change thermal storage-release properties. So it can be formulated that the nanoscale CA-MA/SiO_2 composite PCM with the form-stable property, good thermal storage capacity and relatively low thermal conductivity can be applied for energy conservation as a kind of thermal functional material.
基金Funded by the Major State Research Development Program of China during the 13th Five-Year Plan Period(No.2016YFC0700904)the Science and Technology Support Program of Hubei Province(Nos.2014BAA134 and 2015BAA107)
文摘In order to improve the thermal storage capacity of expanded vermiculite(EV) based formstable composite PCM(FS-PCM) via organic modification of EV, first, EV was modified with a sodium stearate(Na St) as surface modifier, and organic EV(OEV) with hydrophobicity and higher adsorption capacity for fatty acid was obtained. A novel capric-stearic acid eutectic(CA-SA)/OEV FS-PCM with high thermal storage capacity was then developed. OEV and CA-SA/OEV were characterized by scanning electron microscopy(SEM), X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FTIR), differential scanning calorimetry(DSC), thermal gravimetry(TG), and thermal cycling test. Results showed that OEV has obvious hydrophobicity and a higher adsorption capacity for fatty acid. Its adsorption ratio has increased by 48.71% compared with that of EV. CA-SA/OEV possesses high thermal storage density(112.52 J/g), suitable melting temperature(20.49 ℃), good chemical compatibility, excellent thermal stability and reliability, indicating great application potential for building energy efficiency. Moreover, organic modification of inorganic matrix may offer novel options for improving its adsorption capacity for organic PCMs and increasing heat storage capacity of corresponding FS-PCMs.
文摘CE (=%C+(1/3)x(%Si)) does not suit experiment results in many cases. In this work, the effect of alloy elements on primary crystal temperature was measured and the relationship between primary crystal temperature (Tc) and carbon equivalent (CEL) was investigated. The results show that Tc (Celsius degree) = 1650-110 × (%C) -25 × (%Si)+3 × (%Mn) -35 × (%P) -71 × (%5)-2 × (%Ni) -7 × (%Cr); CEL=%C + 0.23×(%Si)-0.03× (%Mn)+0.32×(%P)+0.64×(%S) +0.02×(%Ni)+0.06×(%Cr). That is, in hypo eutectic composition, carbon equivalent should be calculated with CEL=%C+ 0.23×(%Si), not with CE=%C+(1/3) x(%Si).
基金This work was supported financially by the National Natural Science Foundation of China(No.51201121)the Science and Technology Foundation for Selected Overseas Chinese Scholars of Shaanxi Province(2015)+1 种基金the Key Industry Innovation Chain(group)Project of Shaanxi Province(No.2019ZDLGY 04-04)the Research Project of Shaanxi Engineering Technology Research Center for Wear-resisting Materials(No.2016NMZX03).
文摘Fe-Al-Ta eutectic composites were obtained by a modified Bridgman directional solidification technique at different solidification rates.Solidification microstructure transforms from regular eutectic to eutectic colony with the increase of the solidification rate.The solid/liquid interface of Fe-Al-Ta eutectic evolves from planar interface to cellular interface with the increase of the solidification rate.In addition,threepoint bending method was adopted to study the room-temperature fracture toughness of the as-cast Fe-Al-Ta eutectic alloy and the Fe-Al-Ta eutectic composites.Moreover,the fracture morphologies,the crack propagation path and the strengthening mechanism of Fe-Al-Ta eutectic were discussed.
基金Project supported by National Natural Science Foundation of China(51141007)
文摘In the present paper, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and X-ray diffraction (XRD) were used to examine the effects of a Sr-Y composite modifier on the microstructure of A356 alloy. After adding Y to A356, YAl 3 compounds formed, and the size of the α (Al) crystal nucleus increased. The degree of supercooling caused by Sr-Y composite modifier was higher than Sr modification by 2.7 °C, leading to an increased nucleation rate. This increase in supercooling temperature was favorable to the refinement of eutectic structure of the alloy and its eutectic reaction was delayed to the maximum extent. The Si phase in the as-cast Sr-Y composite-modified A356 alloy was either granular or flaky. No large flakes of eutectic Si were found, and the modification effects were completely comparable with those obtained using a lone Sr modifier. After T6 heat treatment, most of the eutectic Si showed a grain-like shape with smaller grains. No eutectic Si with long-strip shapes, significant enhancements in the particle roundness and evenness of the Si crystals, and increased globosity were observed. Both the roundness and evenness of the grained Si crystals were enhanced, and the amount of globular eutectic Si available increased, these findings showed that excellent modification effects were achieved.
基金supported by the National Natural Science Foundation of China(21573077,51373055)the International Lead and Zinc Research Organization Foundation(ILZRO/IZA/CN201212)
文摘In order to confirm the eutectic composition, eutectic temperature and phases of Al-rich Al-RE(La, Ce, Pr, Nd) binary systems, the eutectic Al-RE alloys with the controversial compositions were investigated. The scanning electron microscopy/energy dispersive spectroscopy(SEM/EDS), differential scanning calorimetric(DSC) and cooling curve tests analysis indicated that a similar eutectic composition(~12 wt.% RE) on the Al-rich region was observed in the Al-La, Al-Ce, Al-Pr and Al-Nd alloys, and the eutectic structure of the alloys was consisted of α-Al and α-Al11RE3 phases by combining with X-ray diffraction(XRD) tests. In addition, the eutectic temperatures determined by DSC and cooling curve tests were very close and around 645 oC.
基金supported by the National Key R&D Program of China(No.2021YFB3702300)the National Natural Science Foundation of China(No.52022042)+2 种基金the Project of the Science Center for Gas Turbine(No.HT-P2022-DB-Ⅳ-002-001)the National Science and Technology Major Project(No.J2019-Ⅶ−0008-0148)the Research on the Development and Preparation of Thermal Barrier Coating Materials on New Generation of Heavy-duty Gas Turbines(No.UGTC-HT-WXKT-2022-032).
文摘Although rare earth zirconates(RE_(2)Zr_(2)O_(7))have garnered attention as viable candidates for thermal barrier coatings(TBCs),they suffer from low fracture toughness and accelerated calcium–magnesium–alumina–silicate(CMAS)melt corrosion at high service temperatures,which impedes their practical application.In this work,we developed a series of REAlO_(3)/RE_(2)Zr_(2)O_(7)(RE=La,Nd,Sm,Eu,Gd,and Dy)composites with a eutectic composition that not only significantly enhanced the fracture toughness by more than 40%relative to that of RE_(2)Zr_(2)O_(7)but also exhibited improved resistance to CMAS corrosion.The increase in toughness arises from multiple mechanisms,such as ferroelastic toughening,fine-grain strengthening,and residual stress toughening,all of which trigger more crack defects and energy consumption.Additionally,the CMAS penetration depth of the REAlO_(3)/RE_(2)Zr_(2)O_(7)composites is approximately 36%lower than that of RE_(2)Zr_(2)O_(7).Al–O constituents in composites can capture CaO,SiO_(2),and MgO in CMAS melts and increase their viscosity,resulting in enhanced CMAS corrosion resistance.The thermophysical properties of the REAlO_(3)/RE_(2)Zr_(2)O_(7)composites were also investigated,and their coefficient of thermal expansion and thermal conductivity are comparable to those of 7–8 wt%Y_(2)O_(3)partially stabilized ZrO2(YSZ),indicating their potential as TBC materials.
基金This work was supported by the International Cooperation Projects of Sichuan Provincial Department of Science and Technology(No.2021YFH0126)Quzhou Science and Technology Bureau Project(No.2021D006)+2 种基金the Fundamental Research Funds for the Central Universities(No.A030202063008029)The China Postdoctoral Science Foundation(Nos.2021T140433,2020M683408)the Natural Science Foundation of Shaanxi Province(No.2021JQ-538).
文摘Polymer-based solid electrolytes have been extensively studied for solid-state lithium metal batteries to achieve high energy density and reliable security.But,its practical application is severely limited by low ionic conductivity and slow Li+transference.Herein,based on the“binary electrolytes”of poly(vinylidene fluoride-chlorotrifluoroethylene)(P(VDF-CTFE))and lithium salt(LiTFSI),a kind of eutectogel hybrid electrolytes(EHEs)with high Li+transference number was developed via tuning the spontaneous coupling of charge and vacated space generated by Li-cation diffusion utilizing the Li6.4La3Zr1.4Ta0.6O12(LLZTO)dopant.LLZTO doping promotes the dissociation of lithium salt,increases Li+carrier density,and boosts ion jumping and the coordination/decoupling reactions of Li+.As a result,the optimized EHEs-10%possess a high Li-transference number of 0.86 and a high Li+conductivity of 3.2×10–4 S·cm–1 at room temperature.Moreover,the prepared EHEs-10%composite solid electrolyte presents excellent lithiumphilic and compatibility,and can be tested stably for 1,200 h at 0.3 mA·cm–2 with assembled lithium symmetric batteries.Likewise,the EHEs-10%films match well with high-loading LiFePO4 and LiCoO2 cathodes(>10 mg·cm–2)and exhibit remarkable interface stability.Particularly,the LiFePO4//EHEs-10%//Li and LiCoO2//EHEs-10%//Li cells deliver high rate performance of 118 mAh·g–1 at 1 C and 93.7 mAh·g–1 at 2 C with coulombic efficiency of 99.3%and 98.1%,respectively.This work provides an in-depth understanding and new insights into our design for polymer electrolytes with fast Li+diffusion.
基金the National Natural ScienceFoundation of China (No. 50102004)the Aeronau-tical Science Foundation of China (No. 04G53048)+3 种基金the Development Program for Outstanding Persons in NPUand the Science Plane Project of Xi an University of Architecture and Technology (projects for talent personsRC0907)the fund of the stale Key Laboratory of Solidifi-cation Processing in NWPU (SKLSP200904)the Education Commission of Shanxi Province of China (095K511)the Doctoral fund of Ministry of Education of China(20096120120017) for financial support