Silicon(Si)is a promising high-capacity anode in lithium-ion batteries but suffers from chronic chemical degradation and capacity fading during calendar aging,greatly hindering its automobile applications.Electrolyte ...Silicon(Si)is a promising high-capacity anode in lithium-ion batteries but suffers from chronic chemical degradation and capacity fading during calendar aging,greatly hindering its automobile applications.Electrolyte engineering currently relies on conventional evaluation criteria of reducing coulombic consumption,which implicitly presume its equivalence to irreversible capacity loss and complicates battery development.We introduce the detrimental ratioρto quantify the fraction of parasitic species that permanently degrades active material.This metric is independent and crucially complements total coulombic consumption for accurate performance evaluation.We systematically investigate multiple electrolyte formulations using high-precision leakage current measurements,open-circuit-voltage experiments,and post-mortem characterizations.Although some electrolytes exhibit similarly low coulombic consumption,they diverge significantly in capacity retention andρ.Especially,dimethyl-carbonate-based localized-high concentration electrolyte can synergically achieve low coulombic consumption and detrimental ratioρduring calendar aging,owing to its chemically inert and structurally resilient solidelectrolyte interface with minimal isolated Si material.By contrast,increasing fluoroethylene carbonate(FEC)additive content suppresses electrolyte breakdown but suffers aggravated chemical degradation of more LixSi isolation for irreversible capacity loss with a risingρ.This study critically reveals that the chemistry-characteristic detrimental ratioρestablishes physically informed performance evaluation to pave the way for accelerating battery development.展开更多
The low-melting glass of Bi2O_(3)-B2O_(3)-SiO_(2)(BiBSi)system was used for the first time for laser sealing of vacuum glazing.Under the condition of constant boron content,how the structure and properties vary with B...The low-melting glass of Bi2O_(3)-B2O_(3)-SiO_(2)(BiBSi)system was used for the first time for laser sealing of vacuum glazing.Under the condition of constant boron content,how the structure and properties vary with Bi/Si ratio in low-melting glass was investigated.In addition,the relationships between laser power,low-melting glass solder with different Bi/Si ratios and laser sealing shear strength were revealed.The results show that a decrease in the Bi/Si ratio can cause a contraction of the glass network of the low-melting glass,leading to an increase of its characteristic temperature and a decrease of its coefficient of thermal expansion.During laser sealing,the copper ions in the low-melting glass play an endothermic role.A change in the Bi/Si ratio will affect the valence state transition of the copper ions in the low-melting glass.The absorbance of the low-melting glass does not follow the expected correlation with the Bi/Si ratio,but shows a linear correlation with the content of divalent copper ions.The greater the concentration of divalent copper ions,the greater the absorbance of the low-melting glass,and the lower the laser power required for laser sealing.The shear strength of the low melting glass solder after laser sealing was tested,and it was found that the maximum shear strength of Z1 glass sample was the highest up to 2.67 MPa.展开更多
The effect of Mg/Si mass ratio on the microstructure and mechanical properties of Al-Mg-Si cast aluminum alloys under sub-rapid solidification conditions was investigated.This study utilized four different Mg/Si ratio...The effect of Mg/Si mass ratio on the microstructure and mechanical properties of Al-Mg-Si cast aluminum alloys under sub-rapid solidification conditions was investigated.This study utilized four different Mg/Si ratios:2.83,1.91,1.73,and 1.53.To analyze the evolution of the microstructure,particularly the second phase,various techniques were employed:optical microscopy(OM),scanning electron microscopy(SEM),energy dispersive spectrometry(EDS),and electron backscatter diffraction(EBSD).Additionally,thermodynamic calculations were performed using the Thermal-calc software to further understand the microstructural changes.Results show that as the Mg/Si ratio decreases from 2.83 to 1.53,α-Al grains become more uniformly distributed.Meanwhile,the morphology of the Mg_(2)Si phases changes from skeletal to short stick shapes with a decreasing aspect ratio.An as-cast Al-Mg-Si alloy with a Mg/Si ratio of 1.53 exhibits high strength,achieving an ultimate tensile strength(UTS)of 320.6 MPa and a yield strength(YS)of 249.9 MPa.The cast alloy with a Mg/Si ratio of 2.83exhibits the highest elongation,reaching 5.31%.This superior elongation is attributed to the uniform distribution of Mg_(2)Si phases,which possess a long skeletal shape.Conversely,the alloy with a Mg/Si ratio of 1.53 demonstrates the lowest elongation,primarily due to the central concentration of Mg_(2)Si phases,which are characterized by their short stick shapes.展开更多
This study employed a wet impregnation method to synthesize five types of Cu/HZSM-5 adsorbents with Si/Al ratios of 25,50,85,200,and 300,used for the removal of H_(2)S in lowtemperature,low-oxygen environments.The imp...This study employed a wet impregnation method to synthesize five types of Cu/HZSM-5 adsorbents with Si/Al ratios of 25,50,85,200,and 300,used for the removal of H_(2)S in lowtemperature,low-oxygen environments.The impact of different Si/Al ratios on the adsorption oxidative performance of Cu_(30)/HZSM-5–85 adsorbents was investigated.According to the performance test results,Cu_(30)/HZSM-5–85 exhibited the highest breakthrough capacity,reaching 231.75 mg H_(2)S/g_(sorbent).Cu/HZSM-5 sorbent maintains a strong ability to remove H_(2)S even under humid conditions and shows excellent water resistance.XRD,BET,and XPS results revealed that CuO is the primary active species,with Cu_(30)/HZSM-5–85 having the largest surface area and highest CuO content,providing more active sites for H_(2)S adsorption.H_(2)-TPR and O_(2)-TPD results confirmed that Cu_(30)/HZSM-5–85 sorbent exhibits outstanding redox properties and oxygen storage capacity,contributing to excellent oxygen transferability in the molecular sieve adsorption-oxidation process.With notable characteristics such as a large surface area,high desulfurization efficiency,and water resistance,Cu_(30)/HZSM-5–85 sorbents hold significant importance for industrial applications.展开更多
Thus far,metal-bonding has presented high efficacy in improving the mechanical,thermal conductive,and anti-corrosion properties of La(Fe,Si)_(13)-based hydrides.However,to ensure high performance,the proportion of met...Thus far,metal-bonding has presented high efficacy in improving the mechanical,thermal conductive,and anti-corrosion properties of La(Fe,Si)_(13)-based hydrides.However,to ensure high performance,the proportion of metal bonders has to be as high as 20 wt%,thereby significantly weakening the magnetocaloric effect(MCE).In this work,small amounts of graphene nanosheets(up to 2 wt%)with high thermal conductivity and specific surface area were incorporated into the La_(0.8)Ce_(0.2)Fe_(11.7)Si_(1.3)Hymatrix through a cold-pressing and sintering process.X-ray diffraction analysis indicates that carbon from graphene can easily diffuse into the lattice of La(Fe,Si)13main phase as an interstitial atom,resulting in a significant increase of the lattice constant accompanied by a significant decrease of the Curie temperature and H content of the composites.While 0.3 wt%graphene doping only has minor improvements in the thermal conductivityλand corrosion resistance of the parent La_(0.8)Ce_(0.2)Fe_(11.7)Si_(1.3)H_(y),further increase of graphene content to 1 wt%causes a significant increase ofλfrom 1.4 W/(m·K)for the parent material to~2 W/(m·K)and a decrease of corrosion current density from 1.43×10^(-5)to 9.63×10^(-6)A/cm^(2).When the graphene content is lower than 0.3 wt%,the large MCE does not significantly deteriorate.In 0-1.5 T,the maximal magnetic-entropy change ASm of 11.5 J/(kg·K)at 336 K for the parent material decreases to 8.2 J/(kg·K)at 306 K for the 2 wt%graphene-dop ed composite.展开更多
Al-Mg-Si-Sc alloys with different Mg/Si ratio(<1.73 in wt.% vs>1.73 in wt.%) and different grain size(coarse grains vs ultrafine grains) were prepared, which allowed to investigate the grain size-dependent Mg/Si...Al-Mg-Si-Sc alloys with different Mg/Si ratio(<1.73 in wt.% vs>1.73 in wt.%) and different grain size(coarse grains vs ultrafine grains) were prepared, which allowed to investigate the grain size-dependent Mg/Si ratio effect on the microstructural evolution and concomitantly on the hardness and electrical conductivity when subjected to aging at 200℃. In the coarse-grained Al-Mg-Sc-Sc alloys, the β" precipitation within the grain interior and also the precipitation hardening were highly dependent on the Mg/Si ratio,while the electrical conductivity was slightly affected by the Mg/Si ratio. A promoted β" precipitation was found in the case of Si excess(Mg/Si ratio <1.73), much greater than in the case of Mg excess(Mg/Si ratio>1.73). While in the ultrafine-grained Al-Mg-Si-Sc alloys, the electrical conductivity rather than the hardness was more sensitive to the Mg/Si ratio. The alloy with Si excess displayed electrical conductivity much higher than its counterpart with Mg excess. This is rationalized by the grain boundary precipitation promoted by Si, which reduced the solute atoms and precipitates within the grain interior. Age softening was found in the ultrafine-grained alloy with Si excess, but the ultrafine-grained alloy with Mg excess held the hardness almost unchanged during the aging. The hardness-conductivity correlation is comprehensively discussed by considering the coupling effect of Mg/Si ratio and grain size. A strategy to simultaneously increase the hardness/strength and electrical conductivity is proposed for the Al-Mg-SiSc alloys, based on present understanding of the predominant factors on strengthening and conductivity,respectively.展开更多
基金supported by the U.S.Department of Energy(DOE),Office of Energy Efficiency and Renewable Energy(EERE),Vehicle Technologies Office(VTO)under the Silicon Consortium Seedling project received by Z.H.Coperated for the DOE Office of Science by UChicago Argonne,LLC,under Contract DE-AC02-06CH11357+2 种基金Pacific Northwest National Laboratory(PNNL)was supported by the U.S.DOE,Office of Advanced Research Projects Agency-Energy(ARPA-E)under the EVs4ALL Program with the contract number DE-AC05-76RL01830operated by Battelle for the DOE under Contract DE-AC0576RL01830performed at the Oak Ridge National Laboratory(GMV)and supported by U.S.DOE’s VTO under the Silicon Consortium Program received by G.M.V.and directed by Carine Steinway,Nicolas Eidson Thomas,Thomas Do。
文摘Silicon(Si)is a promising high-capacity anode in lithium-ion batteries but suffers from chronic chemical degradation and capacity fading during calendar aging,greatly hindering its automobile applications.Electrolyte engineering currently relies on conventional evaluation criteria of reducing coulombic consumption,which implicitly presume its equivalence to irreversible capacity loss and complicates battery development.We introduce the detrimental ratioρto quantify the fraction of parasitic species that permanently degrades active material.This metric is independent and crucially complements total coulombic consumption for accurate performance evaluation.We systematically investigate multiple electrolyte formulations using high-precision leakage current measurements,open-circuit-voltage experiments,and post-mortem characterizations.Although some electrolytes exhibit similarly low coulombic consumption,they diverge significantly in capacity retention andρ.Especially,dimethyl-carbonate-based localized-high concentration electrolyte can synergically achieve low coulombic consumption and detrimental ratioρduring calendar aging,owing to its chemically inert and structurally resilient solidelectrolyte interface with minimal isolated Si material.By contrast,increasing fluoroethylene carbonate(FEC)additive content suppresses electrolyte breakdown but suffers aggravated chemical degradation of more LixSi isolation for irreversible capacity loss with a risingρ.This study critically reveals that the chemistry-characteristic detrimental ratioρestablishes physically informed performance evaluation to pave the way for accelerating battery development.
基金Funded by the National Natural Science Foundation of China(No.52472012)Opening Project of State Silica-Based Materials Laboratory of Anhui Province(No.2022KF11)the Research and Development of Glass Powder for Laser Sealing and Its Sealing Technology(No.K24556)。
文摘The low-melting glass of Bi2O_(3)-B2O_(3)-SiO_(2)(BiBSi)system was used for the first time for laser sealing of vacuum glazing.Under the condition of constant boron content,how the structure and properties vary with Bi/Si ratio in low-melting glass was investigated.In addition,the relationships between laser power,low-melting glass solder with different Bi/Si ratios and laser sealing shear strength were revealed.The results show that a decrease in the Bi/Si ratio can cause a contraction of the glass network of the low-melting glass,leading to an increase of its characteristic temperature and a decrease of its coefficient of thermal expansion.During laser sealing,the copper ions in the low-melting glass play an endothermic role.A change in the Bi/Si ratio will affect the valence state transition of the copper ions in the low-melting glass.The absorbance of the low-melting glass does not follow the expected correlation with the Bi/Si ratio,but shows a linear correlation with the content of divalent copper ions.The greater the concentration of divalent copper ions,the greater the absorbance of the low-melting glass,and the lower the laser power required for laser sealing.The shear strength of the low melting glass solder after laser sealing was tested,and it was found that the maximum shear strength of Z1 glass sample was the highest up to 2.67 MPa.
基金supported by the WQ&UCS (Binzhou)Industrialization Research Institute。
文摘The effect of Mg/Si mass ratio on the microstructure and mechanical properties of Al-Mg-Si cast aluminum alloys under sub-rapid solidification conditions was investigated.This study utilized four different Mg/Si ratios:2.83,1.91,1.73,and 1.53.To analyze the evolution of the microstructure,particularly the second phase,various techniques were employed:optical microscopy(OM),scanning electron microscopy(SEM),energy dispersive spectrometry(EDS),and electron backscatter diffraction(EBSD).Additionally,thermodynamic calculations were performed using the Thermal-calc software to further understand the microstructural changes.Results show that as the Mg/Si ratio decreases from 2.83 to 1.53,α-Al grains become more uniformly distributed.Meanwhile,the morphology of the Mg_(2)Si phases changes from skeletal to short stick shapes with a decreasing aspect ratio.An as-cast Al-Mg-Si alloy with a Mg/Si ratio of 1.53 exhibits high strength,achieving an ultimate tensile strength(UTS)of 320.6 MPa and a yield strength(YS)of 249.9 MPa.The cast alloy with a Mg/Si ratio of 2.83exhibits the highest elongation,reaching 5.31%.This superior elongation is attributed to the uniform distribution of Mg_(2)Si phases,which possess a long skeletal shape.Conversely,the alloy with a Mg/Si ratio of 1.53 demonstrates the lowest elongation,primarily due to the central concentration of Mg_(2)Si phases,which are characterized by their short stick shapes.
基金supported by the National Natural Science Foundation of China(Nos.52270106 and 22266021)Yunnan Major Scientific and Technological Projects(No.202202AG050005)Yunnan Fundamental Research Projects(No.202201AT070116).
文摘This study employed a wet impregnation method to synthesize five types of Cu/HZSM-5 adsorbents with Si/Al ratios of 25,50,85,200,and 300,used for the removal of H_(2)S in lowtemperature,low-oxygen environments.The impact of different Si/Al ratios on the adsorption oxidative performance of Cu_(30)/HZSM-5–85 adsorbents was investigated.According to the performance test results,Cu_(30)/HZSM-5–85 exhibited the highest breakthrough capacity,reaching 231.75 mg H_(2)S/g_(sorbent).Cu/HZSM-5 sorbent maintains a strong ability to remove H_(2)S even under humid conditions and shows excellent water resistance.XRD,BET,and XPS results revealed that CuO is the primary active species,with Cu_(30)/HZSM-5–85 having the largest surface area and highest CuO content,providing more active sites for H_(2)S adsorption.H_(2)-TPR and O_(2)-TPD results confirmed that Cu_(30)/HZSM-5–85 sorbent exhibits outstanding redox properties and oxygen storage capacity,contributing to excellent oxygen transferability in the molecular sieve adsorption-oxidation process.With notable characteristics such as a large surface area,high desulfurization efficiency,and water resistance,Cu_(30)/HZSM-5–85 sorbents hold significant importance for industrial applications.
基金Project supported by the National Natural Science Foundation of China(52171187,52271192)。
文摘Thus far,metal-bonding has presented high efficacy in improving the mechanical,thermal conductive,and anti-corrosion properties of La(Fe,Si)_(13)-based hydrides.However,to ensure high performance,the proportion of metal bonders has to be as high as 20 wt%,thereby significantly weakening the magnetocaloric effect(MCE).In this work,small amounts of graphene nanosheets(up to 2 wt%)with high thermal conductivity and specific surface area were incorporated into the La_(0.8)Ce_(0.2)Fe_(11.7)Si_(1.3)Hymatrix through a cold-pressing and sintering process.X-ray diffraction analysis indicates that carbon from graphene can easily diffuse into the lattice of La(Fe,Si)13main phase as an interstitial atom,resulting in a significant increase of the lattice constant accompanied by a significant decrease of the Curie temperature and H content of the composites.While 0.3 wt%graphene doping only has minor improvements in the thermal conductivityλand corrosion resistance of the parent La_(0.8)Ce_(0.2)Fe_(11.7)Si_(1.3)H_(y),further increase of graphene content to 1 wt%causes a significant increase ofλfrom 1.4 W/(m·K)for the parent material to~2 W/(m·K)and a decrease of corrosion current density from 1.43×10^(-5)to 9.63×10^(-6)A/cm^(2).When the graphene content is lower than 0.3 wt%,the large MCE does not significantly deteriorate.In 0-1.5 T,the maximal magnetic-entropy change ASm of 11.5 J/(kg·K)at 336 K for the parent material decreases to 8.2 J/(kg·K)at 306 K for the 2 wt%graphene-dop ed composite.
基金financially supported by the National Natural Science Foundation of China (No. 51771147)
文摘Al-Mg-Si-Sc alloys with different Mg/Si ratio(<1.73 in wt.% vs>1.73 in wt.%) and different grain size(coarse grains vs ultrafine grains) were prepared, which allowed to investigate the grain size-dependent Mg/Si ratio effect on the microstructural evolution and concomitantly on the hardness and electrical conductivity when subjected to aging at 200℃. In the coarse-grained Al-Mg-Sc-Sc alloys, the β" precipitation within the grain interior and also the precipitation hardening were highly dependent on the Mg/Si ratio,while the electrical conductivity was slightly affected by the Mg/Si ratio. A promoted β" precipitation was found in the case of Si excess(Mg/Si ratio <1.73), much greater than in the case of Mg excess(Mg/Si ratio>1.73). While in the ultrafine-grained Al-Mg-Si-Sc alloys, the electrical conductivity rather than the hardness was more sensitive to the Mg/Si ratio. The alloy with Si excess displayed electrical conductivity much higher than its counterpart with Mg excess. This is rationalized by the grain boundary precipitation promoted by Si, which reduced the solute atoms and precipitates within the grain interior. Age softening was found in the ultrafine-grained alloy with Si excess, but the ultrafine-grained alloy with Mg excess held the hardness almost unchanged during the aging. The hardness-conductivity correlation is comprehensively discussed by considering the coupling effect of Mg/Si ratio and grain size. A strategy to simultaneously increase the hardness/strength and electrical conductivity is proposed for the Al-Mg-SiSc alloys, based on present understanding of the predominant factors on strengthening and conductivity,respectively.
