Microstructures of Ti2AlN/TiAl composites prepared by in-situ method were characterized in in-situ and aging treatment conditions and the nitride precipitation was investigated in Ti2AlN/TiAl composites aged at 900 ℃...Microstructures of Ti2AlN/TiAl composites prepared by in-situ method were characterized in in-situ and aging treatment conditions and the nitride precipitation was investigated in Ti2AlN/TiAl composites aged at 900 ℃ for 24 h after being heat treated at 1400 ℃ for 0.5 h. The in-situ composites consist of γ＋α2 lamellar colonies, equiaxed y grains and Ti2AlN reinforcements. Matrix with nearly fully lamellar structure formed after solution and subsequently aging treatment. With the increase of Ti2AlN content, the nearly fully lamellar structure becomes instable for the aged composites. According to TEM study, fine Ti2AlN precipitates are found to distribute at the grain boundaries of lamellar colony. Needle-like Ti3AlN precipitates arrange in line with growing axis parallel to [001] direction of the γ-TiAl matrix and another needle-like Ti3AlN precipitates with lager size distribute at the dislocations. Key words：展开更多
Total dose effects and single event effects on radiation-hardened power vertical double-diffusion metal oxide semiconductor（VDMOS） devices with composite SiO2-Si3N4 film gates are investigated.The relationships amon...Total dose effects and single event effects on radiation-hardened power vertical double-diffusion metal oxide semiconductor（VDMOS） devices with composite SiO2-Si3N4 film gates are investigated.The relationships among the important electrical parameters of the samples with different thickness SiO2-Si3N4 films,such as threshold voltage,breakdown voltage,and on-state resistance in accumulated dose,are discussed.The total dose experiment results show that the breakdown voltage and the on-state resistance barely change with the accumulated dose.However,the relationships between the threshold voltages of the samples and the accumulated dose are more complex,and not only positively drift,but also negatively drift.At the end of the total dose experiment,we select the group of samples which have the smaller threshold voltage shift to carry out the single event effect studies.We find that the samples with appropriate thickness ratio SiO2-Si3N4 films have a good radiation-hardening ability.This method may be useful in solving both the SEGR and the total dose problems with the composite SiO2-Si3N4 films.展开更多
Piezoelectric effect,plasma effect and semiconductor heterostructure are important strategies for enhanced photocatalytic performance.Herein,we developed a novel heterostructure piezoelectric photocatalyst,Ag/Ag_(2)S/...Piezoelectric effect,plasma effect and semiconductor heterostructure are important strategies for enhanced photocatalytic performance.Herein,we developed a novel heterostructure piezoelectric photocatalyst,Ag/Ag_(2)S/BiFeO_(3)(AAS/BFO),for photocatalytic degradation of ciprofloxacin from water.Experimental results verified the enhancement of combining heterostructure piezoelectric polarization effect,which promotes efficient migration and separation of photogenerated carriers due to the localized surface plasmon resonance effect of Ag nanoparticles.Additionally,the introduction of Ag_(2)S constructs a new heterostructure,that enhances the electron transport rate and improves the separation efficiency on electron-hole pairs.Under ultrasonic stimulation and visible light irradiation,the degradation efficiencies of 15%-AAS/BFO towards ciprofloxacin,methyl orange and methylene blue are significantly enhanced compared to pure BFO fibers.The demonstrated AAS/BFO material based on the synergistic piezoelectric effect and plasmon heterostructure shows potential in efficient organic pollutants water treatment and transforming mechanical energy into chemical energy.展开更多
A hydrophobic coating of the silica fiber reinforced silica composites(SiO2f/SiO2) was synthesized by sol-gel method using methyltriethoxy-silane(MTES) and boric acid(B(OH)3) as raw materials. The relationship among b...A hydrophobic coating of the silica fiber reinforced silica composites(SiO2f/SiO2) was synthesized by sol-gel method using methyltriethoxy-silane(MTES) and boric acid(B(OH)3) as raw materials. The relationship among boron doping, chemical structure of precursors and durability of hydrophobic coatings was discussed. The Si-O-B and methyl groups were successfully introduced in the gel precursors according to the FT-IR and XPS results. The resins were filled in the internal and surface holes of the SiO2f/SiO2 composites partially or completely, which is beneficial to reduce the physical adsorption of the moisture. In addition, hydroxyl groups of the SiO2f/SiO2 composites reacted with the resins and hydrophobic methyl groups were introduced, leading to the reduction of the chemical adsorption of water. Also, the boron doping was beneficial to enhancing the physical cross-linking between the coating and the SiO2f/SiO2 composites, and improved the adhesion of the coating to the substrate. The results show that the optimal hydrophobic coating with contact angle 130.33°, moisture absorption 0.33% and adhesion level 1 is obtained when the molar ratio of MTES to B(OH)3 is 10:4. The real permittivity of M10B4 is constant in the range of 2.32–2.51 and the dielectric tangent loss is constant in the range of 5.5 × 10-4–8.7 × 10-3. The hydrophobic coating has excellent dielectric properties.展开更多
The uniform transparent TiO2/SiO2 photocatalytic composite thin films are prepared by sol-gel method on the soda lime glass substrates, and characterized by UV-visible spectroscopy, X-ray diffraction (XRD), transmissi...The uniform transparent TiO2/SiO2 photocatalytic composite thin films are prepared by sol-gel method on the soda lime glass substrates, and characterized by UV-visible spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), BET surface area, FTIR spectroscopy and X-ray photoelectron spectroscopy (XPS). It was found that the addition of SiO2 to TiO2 thin films can suppress the grain growth of TiO2 crystal, increase the hydroxyl content on the surface of TiO2 films, lower the contact angle for water on TiO, films and enhance the hydrophilic property of TiO2 films. The super-hydrophilic TiO2/SiO2 photocatalytic composite thin films with the contact angle of 0((o) under bar) are obtained by the addition of 10%-20% SiO2 in mole fraction.展开更多
Hollow B–SiO2@TiO2 composites were prepared by the wet chemical deposition method starting from TiCl4 and hollow B–SiO2 microspheres.TiO2 layers composed of anatase TiO2 nanoparticles were coated on the surfaces of ...Hollow B–SiO2@TiO2 composites were prepared by the wet chemical deposition method starting from TiCl4 and hollow B–SiO2 microspheres.TiO2 layers composed of anatase TiO2 nanoparticles were coated on the surfaces of the hollow B–SiO2 microspheres probably through the formation of Ti—O—Si and Ti—O—B bonds.A great number of—OH groups were also present at the TiO2 coating layers.The presence of Ti—O—Si bonds and Ti—O—B bonds resulted in the formation of defects in the TiO2 coating layers,which decreased the band gap of the TiO2 coating layers to ca.3.0 eV and endowed the TiO2 coating layers with visible light absorption performance.The buoyancy hollow B–SiO2@TiO2 composites exhibited high photocatalytic activities for the degradation of ammonia-nitrogen and green algae.The conversion of ammonia-nitrogen reached 65%when the degradation of ammonia-nitrogen(43 mg·L-1 at pH value of 8)was catalyzed by the B–SiO2@TiO2(100:10)composite under the simulated solar light irradiation at 35°C for 660 min.The green algae(5 mg·L-1)were almost completely degraded over the B–SiO@TiO2(100:20)photocatalyst under the visible light irradiation at 35°C for 510 min.展开更多
Ag3PO4 is widely used in the field of photocatalysis because of its unique activity. However, photocorrosion limits its practical application. Therefore, it is very urgent to find a solution to improve the light corro...Ag3PO4 is widely used in the field of photocatalysis because of its unique activity. However, photocorrosion limits its practical application. Therefore, it is very urgent to find a solution to improve the light corrosion resistance of Ag3PO4. Herein, the Z-scheme WO3(H2O)0.333/Ag3PO4 composites are successfully prepared through microwave hydrothermal and simple stirring. The WO3(H2O)0.333/Ag3PO4 composites are characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and UV-Vis spectroscopy. In the degradation of organic pollutants, WO3(H2O)0.333/Ag3PO4 composites exhibit excellent performance under visible light. This is mainly attributed to the synergy of WO3(H2O)0.333 and Ag3PO4. Especially, the photocatalytic activity of 15%WO3(H2O)0.333/Ag3PO4 is the highest, and the methylene blue can be completely degraded in 4 min. In addition, the stability of the composites is also greatly enhanced. After five cycles of testing, the photocatalytic activity of 15%WO3(H2O)0.333/Ag3PO4 is not obviously decreased. However, the degradation efficiency of Ag3PO4 was only 20.2%. This indicates that adding WO3(H2O)0.333 can significantly improve the photoetching resistance of Ag3PO4. Finally, Z-scheme photocatalytic mechanism is investigated.展开更多
In this work,a sponge-like polysulfonamide(PSA)/SiO_2 composite membrane is unprecedentedly prepared by the phase inversion method,and successfully demonstrated as a novel separator of lithium-ion batteries(LIBs).Comp...In this work,a sponge-like polysulfonamide(PSA)/SiO_2 composite membrane is unprecedentedly prepared by the phase inversion method,and successfully demonstrated as a novel separator of lithium-ion batteries(LIBs).Compared to the commercial polypropylene(PP) separator,the sponge-like PSA/SiO_2 composite possesses better physical and electrochemical properties,such as higher porosity,ionic conductivity,thermal stability and flame retarding ability.The LiCoO_2/Li half-cells using the sponge-like composite separator demonstrate superior rate capability and cyclability over those using the commercial PP separator.Moreover,the sponge-like composite separator can ensure the normal operation of LiCoO_2/Li half-cell at an extremely high temperature of 90 °C,while the commercial PP separator cannot.All these encouraging results suggest that this phase inversion based sponge-like PSA/SiO_2 composite separator is really a promising separator for high performance LIBs.展开更多
Supermacroporous composite cryogels embedded with SiO2 nanoparticles were prepared by radical cryogenic copolymerization of the reactive monomer mixture of acrylamide（AAm） and N,N-methylene-bis-acrylamide（MBAAm） c...Supermacroporous composite cryogels embedded with SiO2 nanoparticles were prepared by radical cryogenic copolymerization of the reactive monomer mixture of acrylamide（AAm） and N,N-methylene-bis-acrylamide（MBAAm） containing SiO2 nanoparticles（mass ratios of nanoparticles to the monomer AAm from 0.01 to 0.08） under the freezing-temperature variation condition in glass columns.The properties of these composite cryogels were measured.The height equivalent to theoretical plate（HETP） of the cryogel beds at different liquid flow rates was determined by residence time distribution（RTD） using tracer pulse-response method.The composite cryogel matrix embedded with the mass fraction of SiO2 nanoparticles of 0.02 presented the best properties and was employed in the following graft polymerization.Chromatographic process of lysozyme in the composite cryogel grafted with 2-acrylamido-2-methyl-1-propanesulfonic acid（AMPSA） was carried out to evaluate the protein breakthrough and elution characteristics.The chromatography can be carried out at relatively high superficial velocity,i.e.,15 cm·min-1,indicating the satisfactory mechanical strength due to the embedded nanoparticles.展开更多
Silicon(Si) materials as anode materials for applications in lithium-ion batteries(LIBs) have received increasing attention.Among the Si materials,the electrochemical properties of SiOx-based(0<x≤2)composites are ...Silicon(Si) materials as anode materials for applications in lithium-ion batteries(LIBs) have received increasing attention.Among the Si materials,the electrochemical properties of SiOx-based(0<x≤2)composites are the most prominent.However,due to the cycling stability of SiOx being far from practical,there are some problems,such as Iow initial coulombic efficiency(ICE),obvious volume expansion and poor conductivity.Researchers in various countries have optimized the electrochemical properties of SiOx-based composites by means of pore formation,surface modification,and the choice of constituents.In this review,SiOx-based composites are classified into three categories based on the valency of Si(SiO2 composites,SiO composites and SiOx(0<x<2) composites).The synthesis,morphologies and electrochemical properties of the SiOx-based composites that are applied in LIB are discussed.Finally,the prope rties of several common SiOx-based composites are briefly compared and the challenges faced by SiOx-based composites are highlight.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
A silicon dioxide fiber-reinforced silicon nitride matrix （SiOJSi3N4） composite used for radomes was prepared by chemical vapor infiltration （CVI） process using the SiCl4-NH3-H2 system. The effects of the process ...A silicon dioxide fiber-reinforced silicon nitride matrix （SiOJSi3N4） composite used for radomes was prepared by chemical vapor infiltration （CVI） process using the SiCl4-NH3-H2 system. The effects of the process conditions, including infiltration temperature, infiltration time, and gas flux were investigated. The energy dispersion spectra （EDS） result showed that the main elements of this composite contained Si, N, and O. The X-ray diffraction （XRD） results indicated that phases of the composite before and after treatment at 1350℃ were all amorphous. A little fiber pull-out was observed on the cross section of the composite by scan electron microscope （SEM）. As a result, the composite exhibited good thermal stability, but an appropriate interface was necessary between the fiber and the matrix.展开更多
The micro/nano-scale indentation tests were performed to explore the performance of bisphenol-α-glycidyl methacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) dental resin composites. The effect of the fi...The micro/nano-scale indentation tests were performed to explore the performance of bisphenol-α-glycidyl methacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) dental resin composites. The effect of the filling content of nano-SiO2 particles on the mechanical properties of the dental composites was studied as well. The experimental results showed that the incorporation of the nano-SiO2 particles at low concentrations (up to 10 wt.%) can apparently increase the hardness and elastic modulus of the dental rein composites. The plasticity index indicates a best elastic recovery capability at a proper amount (4 wt.%) of the nanoparticles. Combined with the infrared spectrum, the mechanical enhancement mechanisms of the dental resin composites were analyzed.展开更多
A kind of active composite antibacterial material was prepared with CaHPO4 as the container, Ag^＋ and Zn^2＋ were adsorbed through ion-exchange, then it was doped with small scale of rare earth and photocatalyst, and...A kind of active composite antibacterial material was prepared with CaHPO4 as the container, Ag^＋ and Zn^2＋ were adsorbed through ion-exchange, then it was doped with small scale of rare earth and photocatalyst, and was finally calcined at a certain temperature. The properties and application of the composite material antibacterial were investigated. Some tests show that the as-prepared antibacterial powders modified by opaque agents such os SnO2 and ZrO2, possess beautiful white and excellent climate resistance at normal temperatures and are promising candidate materials for antibacterial plastics and dope. The result of the application in glaze indicates that Ag^＋ can still exist stably, with no color change for the glaze, even being sintered at 1200℃ . SEM , EDS , antibacterial activity analyses and contrast tests reveal that the as-prepared antibacterial powders and the antibacterial glaze both have excellent antibacterial activities, without color change, in the case of dark or brightness.展开更多
基金Project(2011CB605502)supported by the National Basic Research Program of ChinaProject(51001086)supported by the National Natural Science Foundation of China
文摘Microstructures of Ti2AlN/TiAl composites prepared by in-situ method were characterized in in-situ and aging treatment conditions and the nitride precipitation was investigated in Ti2AlN/TiAl composites aged at 900 ℃ for 24 h after being heat treated at 1400 ℃ for 0.5 h. The in-situ composites consist of γ＋α2 lamellar colonies, equiaxed y grains and Ti2AlN reinforcements. Matrix with nearly fully lamellar structure formed after solution and subsequently aging treatment. With the increase of Ti2AlN content, the nearly fully lamellar structure becomes instable for the aged composites. According to TEM study, fine Ti2AlN precipitates are found to distribute at the grain boundaries of lamellar colony. Needle-like Ti3AlN precipitates arrange in line with growing axis parallel to [001] direction of the γ-TiAl matrix and another needle-like Ti3AlN precipitates with lager size distribute at the dislocations. Key words：
文摘Total dose effects and single event effects on radiation-hardened power vertical double-diffusion metal oxide semiconductor（VDMOS） devices with composite SiO2-Si3N4 film gates are investigated.The relationships among the important electrical parameters of the samples with different thickness SiO2-Si3N4 films,such as threshold voltage,breakdown voltage,and on-state resistance in accumulated dose,are discussed.The total dose experiment results show that the breakdown voltage and the on-state resistance barely change with the accumulated dose.However,the relationships between the threshold voltages of the samples and the accumulated dose are more complex,and not only positively drift,but also negatively drift.At the end of the total dose experiment,we select the group of samples which have the smaller threshold voltage shift to carry out the single event effect studies.We find that the samples with appropriate thickness ratio SiO2-Si3N4 films have a good radiation-hardening ability.This method may be useful in solving both the SEGR and the total dose problems with the composite SiO2-Si3N4 films.
基金supported by the National Natural Science Foundation of China(Nos.52372090 and 52073177)the National Natural Science Foundation of Guangdong,China(No.2023A1515010947)Shenzhen Basic Research Program(No.JCYJ20220531102207017).
文摘Piezoelectric effect,plasma effect and semiconductor heterostructure are important strategies for enhanced photocatalytic performance.Herein,we developed a novel heterostructure piezoelectric photocatalyst,Ag/Ag_(2)S/BiFeO_(3)(AAS/BFO),for photocatalytic degradation of ciprofloxacin from water.Experimental results verified the enhancement of combining heterostructure piezoelectric polarization effect,which promotes efficient migration and separation of photogenerated carriers due to the localized surface plasmon resonance effect of Ag nanoparticles.Additionally,the introduction of Ag_(2)S constructs a new heterostructure,that enhances the electron transport rate and improves the separation efficiency on electron-hole pairs.Under ultrasonic stimulation and visible light irradiation,the degradation efficiencies of 15%-AAS/BFO towards ciprofloxacin,methyl orange and methylene blue are significantly enhanced compared to pure BFO fibers.The demonstrated AAS/BFO material based on the synergistic piezoelectric effect and plasmon heterostructure shows potential in efficient organic pollutants water treatment and transforming mechanical energy into chemical energy.
基金supported by the Taishan Scholar Project(No.ts201511080)the National Natural Science Foundation of China(Nos.51672059,51172050,51102060 and 51302050)the Natural Scientific Research Innovation Foundation in Harbin Institute of Technology(No.HIT.NSRIF.2014129)
文摘A hydrophobic coating of the silica fiber reinforced silica composites(SiO2f/SiO2) was synthesized by sol-gel method using methyltriethoxy-silane(MTES) and boric acid(B(OH)3) as raw materials. The relationship among boron doping, chemical structure of precursors and durability of hydrophobic coatings was discussed. The Si-O-B and methyl groups were successfully introduced in the gel precursors according to the FT-IR and XPS results. The resins were filled in the internal and surface holes of the SiO2f/SiO2 composites partially or completely, which is beneficial to reduce the physical adsorption of the moisture. In addition, hydroxyl groups of the SiO2f/SiO2 composites reacted with the resins and hydrophobic methyl groups were introduced, leading to the reduction of the chemical adsorption of water. Also, the boron doping was beneficial to enhancing the physical cross-linking between the coating and the SiO2f/SiO2 composites, and improved the adhesion of the coating to the substrate. The results show that the optimal hydrophobic coating with contact angle 130.33°, moisture absorption 0.33% and adhesion level 1 is obtained when the molar ratio of MTES to B(OH)3 is 10:4. The real permittivity of M10B4 is constant in the range of 2.32–2.51 and the dielectric tangent loss is constant in the range of 5.5 × 10-4–8.7 × 10-3. The hydrophobic coating has excellent dielectric properties.
基金This work was financially supported by the Foundation for University Key Teachers by the Ministry of Education, theKey Resear
文摘The uniform transparent TiO2/SiO2 photocatalytic composite thin films are prepared by sol-gel method on the soda lime glass substrates, and characterized by UV-visible spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), BET surface area, FTIR spectroscopy and X-ray photoelectron spectroscopy (XPS). It was found that the addition of SiO2 to TiO2 thin films can suppress the grain growth of TiO2 crystal, increase the hydroxyl content on the surface of TiO2 films, lower the contact angle for water on TiO, films and enhance the hydrophilic property of TiO2 films. The super-hydrophilic TiO2/SiO2 photocatalytic composite thin films with the contact angle of 0((o) under bar) are obtained by the addition of 10%-20% SiO2 in mole fraction.
基金Supported by the National Natural Science Foundation of China(21506078).
文摘Hollow B–SiO2@TiO2 composites were prepared by the wet chemical deposition method starting from TiCl4 and hollow B–SiO2 microspheres.TiO2 layers composed of anatase TiO2 nanoparticles were coated on the surfaces of the hollow B–SiO2 microspheres probably through the formation of Ti—O—Si and Ti—O—B bonds.A great number of—OH groups were also present at the TiO2 coating layers.The presence of Ti—O—Si bonds and Ti—O—B bonds resulted in the formation of defects in the TiO2 coating layers,which decreased the band gap of the TiO2 coating layers to ca.3.0 eV and endowed the TiO2 coating layers with visible light absorption performance.The buoyancy hollow B–SiO2@TiO2 composites exhibited high photocatalytic activities for the degradation of ammonia-nitrogen and green algae.The conversion of ammonia-nitrogen reached 65%when the degradation of ammonia-nitrogen(43 mg·L-1 at pH value of 8)was catalyzed by the B–SiO2@TiO2(100:10)composite under the simulated solar light irradiation at 35°C for 660 min.The green algae(5 mg·L-1)were almost completely degraded over the B–SiO@TiO2(100:20)photocatalyst under the visible light irradiation at 35°C for 510 min.
基金supported by the National Natural Science Foundation of China(51572103 and 51502106)the Distinguished Young Scholar of Anhui Province(1808085J14)+2 种基金the Foundation for Young Talents in College of Anhui Province(gxyqZD2017051)the Key Foundation of Educational Commission of Anhui Province(KJ2016SD53)the Innovation Team of Design and Application of Advanced Energetic Materials(KJ2015TD003)~~
文摘Ag3PO4 is widely used in the field of photocatalysis because of its unique activity. However, photocorrosion limits its practical application. Therefore, it is very urgent to find a solution to improve the light corrosion resistance of Ag3PO4. Herein, the Z-scheme WO3(H2O)0.333/Ag3PO4 composites are successfully prepared through microwave hydrothermal and simple stirring. The WO3(H2O)0.333/Ag3PO4 composites are characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and UV-Vis spectroscopy. In the degradation of organic pollutants, WO3(H2O)0.333/Ag3PO4 composites exhibit excellent performance under visible light. This is mainly attributed to the synergy of WO3(H2O)0.333 and Ag3PO4. Especially, the photocatalytic activity of 15%WO3(H2O)0.333/Ag3PO4 is the highest, and the methylene blue can be completely degraded in 4 min. In addition, the stability of the composites is also greatly enhanced. After five cycles of testing, the photocatalytic activity of 15%WO3(H2O)0.333/Ag3PO4 is not obviously decreased. However, the degradation efficiency of Ag3PO4 was only 20.2%. This indicates that adding WO3(H2O)0.333 can significantly improve the photoetching resistance of Ag3PO4. Finally, Z-scheme photocatalytic mechanism is investigated.
基金Supported by the funding from "135" Projects Fund of CAS-QIBEBT Director Innovation FoundationThink-Tank Mutual Fund of Qingdao Energy Storage Industry Scientific Research+3 种基金Qingdao Key Lab of Solar Energy Utilization and Energy Storage Technologythe Strategic Priority Research Program of the Chinese Academy of Sciences(XDA09010105)National Natural Science Foundation of China(51502319)Shandong Provincial Natural Science Foundation(ZR2016BQ18)
文摘In this work,a sponge-like polysulfonamide(PSA)/SiO_2 composite membrane is unprecedentedly prepared by the phase inversion method,and successfully demonstrated as a novel separator of lithium-ion batteries(LIBs).Compared to the commercial polypropylene(PP) separator,the sponge-like PSA/SiO_2 composite possesses better physical and electrochemical properties,such as higher porosity,ionic conductivity,thermal stability and flame retarding ability.The LiCoO_2/Li half-cells using the sponge-like composite separator demonstrate superior rate capability and cyclability over those using the commercial PP separator.Moreover,the sponge-like composite separator can ensure the normal operation of LiCoO_2/Li half-cell at an extremely high temperature of 90 °C,while the commercial PP separator cannot.All these encouraging results suggest that this phase inversion based sponge-like PSA/SiO_2 composite separator is really a promising separator for high performance LIBs.
基金Supported by the National Natural Science Foundation of China（20876145） the Natural Science Foundation of Zhejiang Province（Y4080329）
文摘Supermacroporous composite cryogels embedded with SiO2 nanoparticles were prepared by radical cryogenic copolymerization of the reactive monomer mixture of acrylamide（AAm） and N,N-methylene-bis-acrylamide（MBAAm） containing SiO2 nanoparticles（mass ratios of nanoparticles to the monomer AAm from 0.01 to 0.08） under the freezing-temperature variation condition in glass columns.The properties of these composite cryogels were measured.The height equivalent to theoretical plate（HETP） of the cryogel beds at different liquid flow rates was determined by residence time distribution（RTD） using tracer pulse-response method.The composite cryogel matrix embedded with the mass fraction of SiO2 nanoparticles of 0.02 presented the best properties and was employed in the following graft polymerization.Chromatographic process of lysozyme in the composite cryogel grafted with 2-acrylamido-2-methyl-1-propanesulfonic acid（AMPSA） was carried out to evaluate the protein breakthrough and elution characteristics.The chromatography can be carried out at relatively high superficial velocity,i.e.,15 cm·min-1,indicating the satisfactory mechanical strength due to the embedded nanoparticles.
基金supported by the National Natural Science Foundation of China(NSFC,Nos.21671170,21673203, 21201010)the Top-notch Academic Programs Project of Jiangsu Higher Education Institutions(TAPP)+2 种基金Program for New Century Excellent Talents of the University in China(NCET,No.13-0645)Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.XSJCX17-015)the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Silicon(Si) materials as anode materials for applications in lithium-ion batteries(LIBs) have received increasing attention.Among the Si materials,the electrochemical properties of SiOx-based(0<x≤2)composites are the most prominent.However,due to the cycling stability of SiOx being far from practical,there are some problems,such as Iow initial coulombic efficiency(ICE),obvious volume expansion and poor conductivity.Researchers in various countries have optimized the electrochemical properties of SiOx-based composites by means of pore formation,surface modification,and the choice of constituents.In this review,SiOx-based composites are classified into three categories based on the valency of Si(SiO2 composites,SiO composites and SiOx(0<x<2) composites).The synthesis,morphologies and electrochemical properties of the SiOx-based composites that are applied in LIB are discussed.Finally,the prope rties of several common SiOx-based composites are briefly compared and the challenges faced by SiOx-based composites are highlight.
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This study was financially supported by the Key Foundation of National Science in China (No. 90405015), the National Elitist Youth Foundation of China (No. 50425208the Doctorate Foundation of Northwestern Polytechnical University (CX200505).
文摘A silicon dioxide fiber-reinforced silicon nitride matrix （SiOJSi3N4） composite used for radomes was prepared by chemical vapor infiltration （CVI） process using the SiCl4-NH3-H2 system. The effects of the process conditions, including infiltration temperature, infiltration time, and gas flux were investigated. The energy dispersion spectra （EDS） result showed that the main elements of this composite contained Si, N, and O. The X-ray diffraction （XRD） results indicated that phases of the composite before and after treatment at 1350℃ were all amorphous. A little fiber pull-out was observed on the cross section of the composite by scan electron microscope （SEM）. As a result, the composite exhibited good thermal stability, but an appropriate interface was necessary between the fiber and the matrix.
文摘The micro/nano-scale indentation tests were performed to explore the performance of bisphenol-α-glycidyl methacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) dental resin composites. The effect of the filling content of nano-SiO2 particles on the mechanical properties of the dental composites was studied as well. The experimental results showed that the incorporation of the nano-SiO2 particles at low concentrations (up to 10 wt.%) can apparently increase the hardness and elastic modulus of the dental rein composites. The plasticity index indicates a best elastic recovery capability at a proper amount (4 wt.%) of the nanoparticles. Combined with the infrared spectrum, the mechanical enhancement mechanisms of the dental resin composites were analyzed.
文摘A kind of active composite antibacterial material was prepared with CaHPO4 as the container, Ag^＋ and Zn^2＋ were adsorbed through ion-exchange, then it was doped with small scale of rare earth and photocatalyst, and was finally calcined at a certain temperature. The properties and application of the composite material antibacterial were investigated. Some tests show that the as-prepared antibacterial powders modified by opaque agents such os SnO2 and ZrO2, possess beautiful white and excellent climate resistance at normal temperatures and are promising candidate materials for antibacterial plastics and dope. The result of the application in glaze indicates that Ag^＋ can still exist stably, with no color change for the glaze, even being sintered at 1200℃ . SEM , EDS , antibacterial activity analyses and contrast tests reveal that the as-prepared antibacterial powders and the antibacterial glaze both have excellent antibacterial activities, without color change, in the case of dark or brightness.
