As a prevailing cathode material of lithium-ion batteries(LIBs),LiCoO_(2)(LCO)still encounters the tricky problems of structural collapse,whose morphological engineering and cation doping are crucial for surmounting t...As a prevailing cathode material of lithium-ion batteries(LIBs),LiCoO_(2)(LCO)still encounters the tricky problems of structural collapse,whose morphological engineering and cation doping are crucial for surmounting the mechanical strains and alleviating phase degradation upon cycling.Hereinafter,we propose a strategy using a zeolitic imidazolate framework(ZIF)as the self-sacrificing template to directionally prepare a series of LiNi_(0.1)Co_(0.9)O_(2)(LNCO)with tailorable electrochemical properties.The rational selection of sintering temperature imparts the superiority of the resultant products in lithium storage,during which the sample prepared at 700℃(LNCO-700)outperforms its counterparts in cyclability(156.8 mA h g^(-1)at 1 C for 200 cycles in half cells,1 C=275 mA g^(-1))and rate capability due to the expedited ion/electron transport and the strengthen mechanical robustness.The feasibility of proper Ni doping is also divulged by half/full cell tests and theoretical study,during which LNCO-700(167 mA h g^(-1)at 1 C for 100 cycles in full cells)surpasses LCO-700 in battery performance due to the mitigated phase deterioration,stabilized layered structu re,ameliorated electro nic co nductivity,a nd exalted lithium sto rage activity.This work systematically unveils tailorable electrochemical behaviors of LNCO to better direct their practical application.展开更多
PrBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(PrBSCF) has attracted much research interest as a potential triple ionic and electronic conductor(TIEC) electrode for protonic ceramic fuel cells(PCFCs). The chemical formula...PrBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(PrBSCF) has attracted much research interest as a potential triple ionic and electronic conductor(TIEC) electrode for protonic ceramic fuel cells(PCFCs). The chemical formula for Pr BSCF is AA'B_(2)O_(5+δ), with Pr(A-site) and Ba/Sr(A'-site) alternately stacked along the c-axis. Due to these structural features, the bulk oxygen ion diffusivity is significantly enhanced through the disorder-free channels in the PrO layer;thus, the A site cations(lanthanide ions) play a pivotal role in determining the overall electrochemical properties of layered perovskites. Consequently, previous research has predominantly focused on the electrical properties and oxygen bulk/surface kinetics of Ln cation effects,whereas the hydration properties for PCFC systems remain unidentified. Here, we thoroughly examined the proton uptake behavior and thermodynamic parameters for the hydration reaction to conclusively determine the changes in the electrochemical performances depending on LnBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(LnBSCF,Ln=Pr, Nd, and Gd) cathodes. At 500 ℃, the quantitative proton concentration of PrBSCF was 2.04 mol% and progressively decreased as the Ln cation size decreased. Similarly, the Gibbs free energy indicated that less energy was required for the formation of protonic defects in the order of Pr BSCF < Nd BSCF < Gd BSCF. To elucidate the close relationship between hydration properties and electrochemical performances in LnBSCF cathodes, PCFC single cell measurements and analysis of the distribution of relaxation time were further investigated.展开更多
The effect of Na-excess content in the precursor on the structural and electrochemical performances of sodium nickel manganese oxide(NNMO)prepared by sol-gel and electrospinning methods is investigated in this paper.X...The effect of Na-excess content in the precursor on the structural and electrochemical performances of sodium nickel manganese oxide(NNMO)prepared by sol-gel and electrospinning methods is investigated in this paper.X-ray diffraction results of the prepared NNMO without adding Na-excess content indicate sodium loss,while the mixed phase of P2/O′3-type layered NNMO presented after adding Na-excess content.Compared with the sol-gel method,the secondary phase of NiO is more suppressed by using the electrospinning method,which is further confirmed by field emission scanning electron microscope images.N_(2) adsorption-desorption isotherms show no remarkably difference in specific surface areas between different preparation methods and Na-excess contents.The analysis of X-ray absorption near edge structure indicates that the oxidation states of Ni and Mn are+2 and+4,respectively.For the electrochemical properties,superior electrochemical performance is observed in the NNMO electrode with a low Na-excess content of 5wt%.The highest specific capacitance is 36.07 F·g^(-1)at0.1 A·g^(-1)in the NNMO electrode prepared by using the sol-gel method.By contrast,the NNMO electrode prepared using the electrospinning method with decreased Na-excess content shows excellent cycling stability of 100%after charge-discharge measurements for 300 cycles.Therefore,controlling the Na excess in the precursor together with the preparation method is important for improving the electrochemical performance of Na-based electrode materials in supercapacitors.展开更多
The electrochemical reduction of carbon dioxide offers a sound and economically viable technology for the electrification and decarbonization of the chemical and fuel industries.In this technology,an electrocatalytic ...The electrochemical reduction of carbon dioxide offers a sound and economically viable technology for the electrification and decarbonization of the chemical and fuel industries.In this technology,an electrocatalytic material and renewable energy-generated electricity drive the conversion of carbon dioxide into high-value chemicals and carbon-neutral fuels.Over the past few years,single-atom catalysts have been intensively studied as they could provide near-unity atom utilization and unique catalytic performance.Single-atom catalysts have become one of the state-of-the-art catalyst materials for the electrochemical reduction of carbon dioxide into carbon monoxide.However,it remains a challenge for single-atom catalysts to facilitate the efficient conversion of carbon dioxide into products beyond carbon monoxide.In this review,we summarize and present important findings and critical insights from studies on the electrochemical carbon dioxide reduction reaction into hydrocarbons and oxygenates using single-atom catalysts.It is hoped that this review gives a thorough recapitulation and analysis of the science behind the catalysis of carbon dioxide into more reduced products through singleatom catalysts so that it can be a guide for future research and development on catalysts with industry-ready performance for the electrochemical reduction of carbon dioxide into high-value chemicals and carbon-neutral fuels.展开更多
The mechanical properties,contact angle,thermomechanical and electrochemical properties of PE,PVDF,and ceramic separators were compared.The experimental results show that the PE separator has the largest porosity,the ...The mechanical properties,contact angle,thermomechanical and electrochemical properties of PE,PVDF,and ceramic separators were compared.The experimental results show that the PE separator has the largest porosity,the PVDF separator has the best mechanical properties,wettability,and heat resistance.Three kinds of separators were assembled into lithium-ion batteries for electrochemical tests.Among them,the PE separator has the best rate performance,and the ceramic separator has poor performance in charge-discharge cycles.At the same time,the PE and ceramic separators were tested with different amounts of electrolytes at room temperature and a high temperature,and it is found that the capacity of the PE separator is higher at room temperature,while the performance of the ceramic separator is better at a high temperature.The amount of electrolyte also has a certain influence on its electrochemical performance.展开更多
Electrochromic materials are of great interest for their potential in eyewear protection and data storage devices, as they change colors in response to electrochemical switching. While many of the systems currently us...Electrochromic materials are of great interest for their potential in eyewear protection and data storage devices, as they change colors in response to electrochemical switching. While many of the systems currently used are based on inorganic materials, organic materials such as triazenes have emerged as viable alternatives due to their unique properties, including optical properties. Triazenes are a class of organic compounds with three consecutive nitrogen atoms in an acyclic arrangement, and they have been used for a variety of applications in medicinal and synthetic chemistry. However, the effects of solvents on the UV-visible absorption spectrum of triazenes have not been fully investigated. The neutral molecules of 3,3-diisopropyl-1-phenyltriazene and 1-(4-chlorophenyl)-3-cyclopentyltriazene in acetonitrile, the UV-visible spectra corresponded respectively to HOMO → LUMO transitions with a large maximum absorption at 299.74 nm (4.1364 eV) and 299.57 nm (4.1387 eV) and the most intense oscillator strength (f = 0.6988) and (f = 0.7372). These results suggest that the electronic transitions of the compounds are highly influenced by the nature of the substituents on the triazene unit, as well as the solvent used in the experiment. The redox couple 0.92 and -0.44 V/Ag/AgCl is attributed to the phenyl group. Compound III showed an oxidation and reduction peak respectively -0.27 and -0.8 V/Ag/AgCl attributed to the phenyl molecule. The study concluded that all three compounds were electroactive and exhibited reversible characteristics with oxidizing/reducing couples. This study aims to contribute to research on the optical properties of triazenes compounds and the application of quantum chemical calculation methods for understanding their molecular structures. By investigating the solute-solvent interactions occurring in the solvation shell of the solutes, we aim to gain insights into the effects of solvents on the UV-visible absorption spectrum of triazenes. Our findings may have implications for the development of functionalized triazenes as potential electrochromic materials.展开更多
The discovery of efficient,selective,and stable electrocatalysts can be a key point to produce the largescale chemical fuels via electrochemical CO_(2) reduction(ECR).In this study,an earth-abundant and nontoxic ZnO-b...The discovery of efficient,selective,and stable electrocatalysts can be a key point to produce the largescale chemical fuels via electrochemical CO_(2) reduction(ECR).In this study,an earth-abundant and nontoxic ZnO-based electrocatalyst was developed for use in gas-diffusion electrodes(GDE),and the effect of nitrogen(N)doping on the ECR activity of ZnO electrocatalysts was investigated.Initially,a ZnO nanosheet was prepared via the hydrothermal method,and nitridation was performed at different times to control the N-doping content.With an increase in the N-doping content,the morphological properties of the nanosheet changed significantly,namely,the 2D nanosheets transformed into irregularly shaped nanoparticles.Furthermore,the ECR performance of Zn O electrocatalysts with different N-doping content was assessed in 1.0 M KHCO_(3) electrolyte using a gas-diffusion electrode-based ECR cell.While the ECR activity increased after a small amount of N doping,it decreased for higher N doping content.Among them,the N:ZnO-1 h electrocatalysts showed the best CO selectivity,with a faradaic efficiency(FE_(CO))of 92.7%at-0.73 V vs.reversible hydrogen electrode(RHE),which was greater than that of an undoped Zn O electrocatalyst(FE_(CO)of 63.4%at-0.78 V_(RHE)).Also,the N:ZnO-1 h electrocatalyst exhibited outstanding durability for 16 h,with a partial current density of-92.1 mA cm^(-2).This improvement of N:ZnO-1 h electrocatalyst can be explained by density functional theory calculations,demonstrating that this improvement of N:ZnO-1 h electrocatalyst comes from(ⅰ)the optimized active sites lowering the free energy barrier for the rate-determining step(RDS),and(ⅱ)the modification of electronic structure enhancing the electron transfer rate by N doping.展开更多
In order to better understand the specific substituent effects on the electrochemical oxidation process of β-O-4 bond, a series of methoxyphenyl type β-O-4 dimer model compounds with different localized methoxyl gro...In order to better understand the specific substituent effects on the electrochemical oxidation process of β-O-4 bond, a series of methoxyphenyl type β-O-4 dimer model compounds with different localized methoxyl groups, including 2-(2-methoxyphenoxy)-1-phenylethanone, 2-(2-methoxyphenoxy)-1-phenylethanol, 2-(2-methoxyphenoxy)-1-(4-methoxyphenyl)ethanone, 2-(2-methoxyphenoxy)-1-(4-methoxyphenyl)ethanol, 2-(2,6-dimethoxyphenoxy)-1-(4-methoxyphenyl)ethanone, 2-(2,6-dimethoxyphenoxy)-1-(4-methoxyphenyl)ethanol have been selected and their electrochemical properties have been studied experimentally by cyclic voltammetry, and FT-IR spectroelectrochemistry. Combining with electrolysis products distribution analysis and density functional theory calculations, oxidation mechanisms of all six model dimers have been explored. In particular, a total effect from substituents of both para-methoxy(on the aryl ring closing to Cα) and Cα-OH on the oxidation mechanisms has been clearly observed, showing a significant selectivity on the Cα-Cβbond cleavage induced by electrochemical oxidations.展开更多
This work studied the microstructure,mechanical properties and damping properties of Mg_(95.34)Ni_(2)Y_(2.66) and Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloys systematically.The difference in the evolution of the long-period ...This work studied the microstructure,mechanical properties and damping properties of Mg_(95.34)Ni_(2)Y_(2.66) and Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloys systematically.The difference in the evolution of the long-period stacked ordered(LPSO)phase in the two alloys during heat treatment was the focus.The morphology of the as-cast Mg_(95.34)Ni_(2)Y_(2.66)presented a disordered network.After heat treatment at 773 K for 2 hours,the eutectic phase was integrated into the matrix,and the LPSO phase maintained the 18R structure.As Zn partially replaced Ni,the crystal grains became rounded in the cast alloy,and lamellar LPSO phases and more solid solution atoms were contained in the matrix after heat treatment of the Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloy.Both Zn and the heat treatment had a significant effect on damping.Obvious dislocation internal friction peaks and grain boundary internal friction peaks were found after temperature-dependent damping of the Mg_(95.34)Ni_(2)Y_(2.66)and Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloys.After heat treatment,the dislocation peak was significantly increased,especially in the alloy Mg_(95.34)Ni_(2)Y_(2).66.The annealed Mg_(95.34)Ni_(2)Y_(2.66)alloy with a rod-shaped LPSO phase exhibited a good damping performance of 0.14 atε=10^(−3),which was due to the difference between the second phase and solid solution atom content.These factors also affected the dynamic modulus of the alloy.The results of this study will help in further development of high-damping magnesium alloys.展开更多
In recent years,the exploration of seabed has been intensified,but the submarine soils of silt and sand in the Yellow Sea area have not been well investigated so far.In this study,the physical and mechanical propertie...In recent years,the exploration of seabed has been intensified,but the submarine soils of silt and sand in the Yellow Sea area have not been well investigated so far.In this study,the physical and mechanical properties of silt and sand from the Yellow Sea were measured using a direct shear apparatus and their microstructures were observed using a scanning electron microscope.The test results suggest that the shear strength of silt and sand increases linearly with the increase of normal stress.Based on the direct shear test,the scanning electron microscope was used to observe the section surface of sand.It is observed that the section surface becomes rough,with many“V”‐shaped cracks.Many particles appear on the surface of the silt structure and tend to be disintegrated.The X‐ray diffraction experiment reveals that the sand and silt have different compositions.The shear strength of sand is slightly greater than that of silt under high stress,which is related to the shape of soil particles and the mineral composition.These results can be a reference for further study of other soils in the Yellow Sea;meanwhile,they can serve as soil parameters for the stability and durability analyses of offshore infrastructure construction.展开更多
For the challenging nature of the zirconium environment analysis, this study consists to analyze the electrochemical behavior of Zirconium in both aqueous and organic media. To that end first the electrolytic media wa...For the challenging nature of the zirconium environment analysis, this study consists to analyze the electrochemical behavior of Zirconium in both aqueous and organic media. To that end first the electrolytic media was selected on the basis of the Pourbaix potential-pH diagram, which provides informations on the predominance of Zr<sup>(IV) </sup> ion and Zr in aqueous media. In aqueous media, analyzes were first carried out in acidic media then in basic media. Studies have thus revealed that the acidic environment is not favourable for the electrochemical analysis of zirconium. Voltammograms obtained in an acidic environment show no zirconium detection signal;this is due to the strong presence of H<sup>+</sup> ions in the solution. We have also observed in acidic media the phenomenon of passivation of the electrode surface. In aqueous alkaline media (pH = 13), we have drawn in reduction several Intensity-Potential curves by fixingsome technical parameterslike scanning speed, rotation speed of the electrode. The obtained voltammograms show cathodic waves, starting from -1.5 V/DHW and attributed to the reduction of Zr<sup> (IV) </sup> to Zr (0). The last phase of this study focused on the electrochemical analysis of zirconium in an organic media. In this media, several intensity-potential curves were plotted in reduction and in cyclic voltammetry with various parameters. Through several reduction analysis, the Zr<sup> (IV) </sup> was reduced to Zr (0) to the potential of -1.5 V/DHW. The electrochemical analysis of zirconium in organic media seems globally easier to achieve thanks to its large solvent window (i.e. dimethylformamide (DMF) solvent window > 6 V).展开更多
The purpose of this research is to investigate the hydration behavior and cementitious properties of the mixture of calcium carbonate and aluminate, and to explore whether it can be adopted as a new low-carbon cementi...The purpose of this research is to investigate the hydration behavior and cementitious properties of the mixture of calcium carbonate and aluminate, and to explore whether it can be adopted as a new low-carbon cementitious material. The composite system of calcium carbonate and aluminate minerals is studied by measuring the component of hydration products, the hydration heat, setting time and compressive strength.The results prove that the composite system has certain cementitious properties and is feasible to prepare new low-carbon cement.展开更多
Saturation magnetization,magneto-crystalline anisotropy field,and dielectric properties are closely related to microwave devices applied at different frequencies.For regulating the magnetic and dielectric properties o...Saturation magnetization,magneto-crystalline anisotropy field,and dielectric properties are closely related to microwave devices applied at different frequencies.For regulating the magnetic and dielectric properties of W-type barium ferrites,single-phase BaMe_(2)Fe_(16)O_(27)(Me=Fe,Mn,Zn,Ni,Co) with different Me ions were synthesized by the high-temperature solid-state method.The saturation magnetization(Ms) range from 47.77 emu/g to 95.34 emu/g and the magnetic anisotropy field(H_a) range from 10700.60 Oe(1 Oe=79.5775 A·m^(-1)) to 13739.57 Oe,depending on the type of cation substitution in the hexagonal lattice.The dielectric permittivity and dielectric loss decrease with increasing frequency of the AC electric field in the low-frequency region,while they almost remain constant in the high-frequency region.The charac teristics of easy regulation and preparation make it a potential candidate for use in microwave device applications.展开更多
Dissolved oxygen(DO)usually refers to the amount of oxygen dissolved in water.In the environment,medicine,and fermentation industries,the DO level needs to be accurate and capable of online monitoring to guide the pre...Dissolved oxygen(DO)usually refers to the amount of oxygen dissolved in water.In the environment,medicine,and fermentation industries,the DO level needs to be accurate and capable of online monitoring to guide the precise control of water quality,clinical treatment,and microbial metabolism.Compared with other analytical methods,the electrochemical strategy is superior in its fast response,low cost,high sensitivity,and portable device.However,an electrochemical DO sensor faces a trade-off between sensitivity and long-term stability,which strongly limits its practical applications.To solve this problem,various advanced nanomaterials have been proposed to promote detection performance owing to their excellent electrocatalysis,conductivity,and chemical stability.Therefore,in this review,we focus on the recent progress of advanced nanomaterial-based electrochemical DO sensors.Through the comparison of the working principles on the main analysis techniques toward DO,the advantages of the electrochemical method are discussed.Emphasis is placed on recently developed nanomaterials that exhibit special characteristics,including nanostructures and preparation routes,to benefit DO determination.Specifically,we also introduce some interesting research on the configuration design of the electrode and device,which is rarely introduced.Then,the different requirements of the electrochemical DO sensors in different application fields are included to provide brief guidance on the selection of appropriate nanomaterials.Finally,the main challenges are evaluated to propose future development prospects and detection strategies for nanomaterial-based electrochemical sensors.展开更多
The application of Mg-based electrochemical energy storage materials in high performance supercapacitors is an essential step to promote the exploitation and utilization of magnesium resources in the field of energy s...The application of Mg-based electrochemical energy storage materials in high performance supercapacitors is an essential step to promote the exploitation and utilization of magnesium resources in the field of energy storage.Unfortunately,the inherent chemical properties of magnesium lead to poor cycling stability and electrochemical reactivity,which seriously limit the application of Mg-based materials in supercapacitors.Herein,in this review,more than 70 research papers published in recent 10 years were collected and analyzed.Some representative research works were selected,and the results of various regulative strategies to improve the electrochemical performance of Mg-based materials were discussed.The effects of various regulative strategies(such as constructing nanostructures,synthesizing composites,defect engineering,and binder-free synthesis,etc.)on the electrochemical performance and their mechanism are demonstrated using spinelstructured MgX_(2)O_(4) and layered structured Mg-X-LDHs as examples.In addition,the application of magnesium oxide and magnesium hydroxide in electrode materials,MXene's solid spacers and hard templates are introduced.Finally,the challenges and outlooks of Mg-based electrochemical energy storage materials in high performance supercapacitors are also discussed.展开更多
The development of lithium-sulfur(Li-S)batteries is hindered by the disadvantages of shuttling of polysulfides and the sluggish redox kinetics of the conversion of sulfur species during discharge and charge.Herein,the...The development of lithium-sulfur(Li-S)batteries is hindered by the disadvantages of shuttling of polysulfides and the sluggish redox kinetics of the conversion of sulfur species during discharge and charge.Herein,the crystallinities of a titanium nitride(TiN)film on copper-embedded carbon nanofibers(Cu-CNFs)are regulated and the nanofibers are used as interlayers to resolve the aforementioned crucial issues.A low-crystalline TiN-coated Cu-CNF(L-TiN-Cu-CNF)interlayer is compared with its highly crystalline counterpart(H-TiN-Cu-CNFs).It is demonstrated that the L-TiN coating not only strengthens the chemical adsorption toward polysulfides but also greatly accelerates the electrochemical conversion of polysulfides.Due to robust carbon frameworks and enhanced kinetics,impressive highrate performance at 2 C(913 mAh g^(-1)based on sulfur)as well as remarkable cyclic stability up to 300 cycles(626 mAh g^(-1))with capacity retention of 46.5%is realized for L-TiN-Cu-CNF interlayer-configured Li-S batteries.Even under high loading(3.8 mg cm^(-2))of sulfur and relatively lean electrolyte(10μL electrolyte per milligram sulfur)conditions,the Li-S battery equipped with L-TiN-Cu-CNF interlayers delivers a high capacity of 1144 mAh g^(-1)with cathodic capacity of 4.25 mAh cm^(-2)at 0.1 C,providing a potential pathway toward the design of multifunctional interlayers for highly efficient Li-S batteries.展开更多
The durability of reinforced concrete structures is greatly influenced by the corrosion of the reinforcement. In addition to air pollution related to the repair of corroded structures, chloride ions are the main facto...The durability of reinforced concrete structures is greatly influenced by the corrosion of the reinforcement. In addition to air pollution related to the repair of corroded structures, chloride ions are the main factors of corrosion of reinforced concrete structures. This study aims to valorize a clay inhibitor against reinforcement corrosion in reinforced concrete. This clay (Attapulgite) was incorporated into reinforced concretes at different percentages of substitution of calcined attapulgite (0%, 5% and 10%) to cement in the formulation. The corrosion inhibitory power of attapulgite is evaluated in reinforced concretes subjected to the action of chloride ions at different intervals in the NaCl solution (1 day, 21 days and 45 days) by electrochemical methods (zero current chronopotentiometry, polarization curves and electrochemical impedance spectroscopy). This study showed that in the presence of chloride ions, the composition based on 10% attapulgite has an appreciable inhibitory effect with an average inhibitory efficiency of 82%.展开更多
Adopting a nano-and micro-structuring approach to fully unleashing the genuine potential of electrode active material benefits in-depth understandings and research progress toward higher energy density electrochemical...Adopting a nano-and micro-structuring approach to fully unleashing the genuine potential of electrode active material benefits in-depth understandings and research progress toward higher energy density electrochemical energy stor-age devices at all technology readiness levels.Due to various challenging issues,especially limited stability,nano-and micro-structured(NMS)electrodes undergo fast electrochemical performance degradation.The emerging NMS scaffold design is a pivotal aspect of many electrodes as it endows them with both robustness and electrochemical performance enhancement,even though it only occupies comple-mentary and facilitating components for the main mechanism.However,extensive efforts are urgently needed toward optimizing the stereoscopic geometrical design of NMS scaffolds to minimize the volume ratio and maximize their functionality to fulfill the ever-increasing dependency and desire for energy power source supplies.This review will aim at highlighting these NMS scaffold design strategies,summariz-ing their corresponding strengths and challenges,and thereby outlining the potential solutions to resolve these challenges,design principles,and key perspectives for future research in this field.Therefore,this review will be one of the earliest reviews from this viewpoint.展开更多
The laser powder bed fusion(LPBF) process can integrally form geometrically complex and high-performance metallic parts that have attracted much interest,especially in the molds industry.The appearance of the LPBF mak...The laser powder bed fusion(LPBF) process can integrally form geometrically complex and high-performance metallic parts that have attracted much interest,especially in the molds industry.The appearance of the LPBF makes it possible to design and produce complex conformal cooling channel systems in molds.Thus,LPBF-processed tool steels have attracted more and more attention.The complex thermal history in the LPBF process makes the microstructural characteristics and properties different from those of conventional manufactured tool steels.This paper provides an overview of LPBF-processed tool steels by describing the physical phenomena,the microstructural characteristics,and the mechanical/thermal properties,including tensile properties,wear resistance,and thermal properties.The microstructural characteristics are presented through a multiscale perspective,ranging from densification,meso-structure,microstructure,substructure in grains,to nanoprecipitates.Finally,a summary of tool steels and their challenges and outlooks are introduced.展开更多
Magnesium(Mg)-based bone implants degrade rapidly in the physiological environment of the human body which affects their structural integrity and biocompatibility before adequate bone repair.Rare earth elements(REEs)h...Magnesium(Mg)-based bone implants degrade rapidly in the physiological environment of the human body which affects their structural integrity and biocompatibility before adequate bone repair.Rare earth elements(REEs)have demonstrated their effectiveness in tailoring the corrosion and mechanical behavior of Mg alloys.This study methodically investigated the impacts of scandium(Sc)and terbium(Tb)in tailoring the corrosion resistance,mechanical properties,and biocompatibility of Mg–0.5Zn–0.35Zr–0.15Mn(MZZM)alloys fabricated via casting and hot extrusion.Results indicate that addition of Sc and Tb improved the strength of MZZM alloys via grain size reduction and solid solution strengthening mechanisms.The extruded MZZM–(1–2)Sc–(1–2)Tb(wt.%)alloys exhibit compressive strengths within the range of 336–405 MPa,surpassing the minimum required strength of 200 MPa for bone implants by a significant margin.Potentiodynamic polarization tests revealed low corrosion rates of as–cast MZZM(0.25 mm/y),MZZM–2Tb(0.45 mm/y),MZZM–1Sc–1Tb(0.18 mm/y),and MZZM–1Sc–2Tb(0.64 mm/y),and extruded MZZM(0.17 mm/y),MZZM–1Sc(0.15 mm/y),MZZM-2Sc(0.45 mm/y),MZZM-1Tb(0.17 mm/y),MZZM-2Tb(0.10 mm/y),MZZM–1Sc-1Tb(0.14 mm/y),MZZM-1Sc-2Tb(0.40 mm/y),and MZZM–2Sc–2Tb(0.51 mm/y)alloys,which were found lower compared to corrosion rate of high-purity Mg(~1.0 mm/y)reported in the literature.Furthermore,addition of Sc,or Tb,or Sc and Tb to MZZM alloys did not adversely affect the viability of SaOS2 cells,but enhanced their initial cell attachment,proliferation,and spreading shown via polygonal shapes and filipodia.This study emphasizes the benefits of incorporating Sc and Tb elements in MZZM alloys,as they effectively enhance corrosion resistance,mechanical properties,and biocompatibility simultaneously.展开更多
基金the financial support from the Special Funds for the Cultivation of Guangdong College Students’Scientific and Technological Innovation(“Climbing Program”Special Funds,pdjh2023b0145)Guangdong Provincial International Joint Research Center for Energy Storage Materials(2023A0505090009)。
文摘As a prevailing cathode material of lithium-ion batteries(LIBs),LiCoO_(2)(LCO)still encounters the tricky problems of structural collapse,whose morphological engineering and cation doping are crucial for surmounting the mechanical strains and alleviating phase degradation upon cycling.Hereinafter,we propose a strategy using a zeolitic imidazolate framework(ZIF)as the self-sacrificing template to directionally prepare a series of LiNi_(0.1)Co_(0.9)O_(2)(LNCO)with tailorable electrochemical properties.The rational selection of sintering temperature imparts the superiority of the resultant products in lithium storage,during which the sample prepared at 700℃(LNCO-700)outperforms its counterparts in cyclability(156.8 mA h g^(-1)at 1 C for 200 cycles in half cells,1 C=275 mA g^(-1))and rate capability due to the expedited ion/electron transport and the strengthen mechanical robustness.The feasibility of proper Ni doping is also divulged by half/full cell tests and theoretical study,during which LNCO-700(167 mA h g^(-1)at 1 C for 100 cycles in full cells)surpasses LCO-700 in battery performance due to the mitigated phase deterioration,stabilized layered structu re,ameliorated electro nic co nductivity,a nd exalted lithium sto rage activity.This work systematically unveils tailorable electrochemical behaviors of LNCO to better direct their practical application.
基金supported by the National Research Foundation (NRF) grant funded by the Korea government (NRF2022R1C1C1007619, NRF-2021M3H4A1A01002921, NRF2021M3I3A1084292)supported by the KIST Institutional Program (Project No. 2E32592-23-069)。
文摘PrBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(PrBSCF) has attracted much research interest as a potential triple ionic and electronic conductor(TIEC) electrode for protonic ceramic fuel cells(PCFCs). The chemical formula for Pr BSCF is AA'B_(2)O_(5+δ), with Pr(A-site) and Ba/Sr(A'-site) alternately stacked along the c-axis. Due to these structural features, the bulk oxygen ion diffusivity is significantly enhanced through the disorder-free channels in the PrO layer;thus, the A site cations(lanthanide ions) play a pivotal role in determining the overall electrochemical properties of layered perovskites. Consequently, previous research has predominantly focused on the electrical properties and oxygen bulk/surface kinetics of Ln cation effects,whereas the hydration properties for PCFC systems remain unidentified. Here, we thoroughly examined the proton uptake behavior and thermodynamic parameters for the hydration reaction to conclusively determine the changes in the electrochemical performances depending on LnBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(LnBSCF,Ln=Pr, Nd, and Gd) cathodes. At 500 ℃, the quantitative proton concentration of PrBSCF was 2.04 mol% and progressively decreased as the Ln cation size decreased. Similarly, the Gibbs free energy indicated that less energy was required for the formation of protonic defects in the order of Pr BSCF < Nd BSCF < Gd BSCF. To elucidate the close relationship between hydration properties and electrochemical performances in LnBSCF cathodes, PCFC single cell measurements and analysis of the distribution of relaxation time were further investigated.
基金financially supported by (i) Suranaree University of Technology,(ii) Thailand Science Research and Innovation,and (iii) National Science,Research and Innovation Fund(project codes 90464 and 160363)。
文摘The effect of Na-excess content in the precursor on the structural and electrochemical performances of sodium nickel manganese oxide(NNMO)prepared by sol-gel and electrospinning methods is investigated in this paper.X-ray diffraction results of the prepared NNMO without adding Na-excess content indicate sodium loss,while the mixed phase of P2/O′3-type layered NNMO presented after adding Na-excess content.Compared with the sol-gel method,the secondary phase of NiO is more suppressed by using the electrospinning method,which is further confirmed by field emission scanning electron microscope images.N_(2) adsorption-desorption isotherms show no remarkably difference in specific surface areas between different preparation methods and Na-excess contents.The analysis of X-ray absorption near edge structure indicates that the oxidation states of Ni and Mn are+2 and+4,respectively.For the electrochemical properties,superior electrochemical performance is observed in the NNMO electrode with a low Na-excess content of 5wt%.The highest specific capacitance is 36.07 F·g^(-1)at0.1 A·g^(-1)in the NNMO electrode prepared by using the sol-gel method.By contrast,the NNMO electrode prepared using the electrospinning method with decreased Na-excess content shows excellent cycling stability of 100%after charge-discharge measurements for 300 cycles.Therefore,controlling the Na excess in the precursor together with the preparation method is important for improving the electrochemical performance of Na-based electrode materials in supercapacitors.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIP)(NRF,2021R1C1C1013953,2022K1A4A7A04094394,2022K1A4A7A04095890)。
文摘The electrochemical reduction of carbon dioxide offers a sound and economically viable technology for the electrification and decarbonization of the chemical and fuel industries.In this technology,an electrocatalytic material and renewable energy-generated electricity drive the conversion of carbon dioxide into high-value chemicals and carbon-neutral fuels.Over the past few years,single-atom catalysts have been intensively studied as they could provide near-unity atom utilization and unique catalytic performance.Single-atom catalysts have become one of the state-of-the-art catalyst materials for the electrochemical reduction of carbon dioxide into carbon monoxide.However,it remains a challenge for single-atom catalysts to facilitate the efficient conversion of carbon dioxide into products beyond carbon monoxide.In this review,we summarize and present important findings and critical insights from studies on the electrochemical carbon dioxide reduction reaction into hydrocarbons and oxygenates using single-atom catalysts.It is hoped that this review gives a thorough recapitulation and analysis of the science behind the catalysis of carbon dioxide into more reduced products through singleatom catalysts so that it can be a guide for future research and development on catalysts with industry-ready performance for the electrochemical reduction of carbon dioxide into high-value chemicals and carbon-neutral fuels.
基金National Natural Science Foundation of China(No.51976143)。
文摘The mechanical properties,contact angle,thermomechanical and electrochemical properties of PE,PVDF,and ceramic separators were compared.The experimental results show that the PE separator has the largest porosity,the PVDF separator has the best mechanical properties,wettability,and heat resistance.Three kinds of separators were assembled into lithium-ion batteries for electrochemical tests.Among them,the PE separator has the best rate performance,and the ceramic separator has poor performance in charge-discharge cycles.At the same time,the PE and ceramic separators were tested with different amounts of electrolytes at room temperature and a high temperature,and it is found that the capacity of the PE separator is higher at room temperature,while the performance of the ceramic separator is better at a high temperature.The amount of electrolyte also has a certain influence on its electrochemical performance.
文摘Electrochromic materials are of great interest for their potential in eyewear protection and data storage devices, as they change colors in response to electrochemical switching. While many of the systems currently used are based on inorganic materials, organic materials such as triazenes have emerged as viable alternatives due to their unique properties, including optical properties. Triazenes are a class of organic compounds with three consecutive nitrogen atoms in an acyclic arrangement, and they have been used for a variety of applications in medicinal and synthetic chemistry. However, the effects of solvents on the UV-visible absorption spectrum of triazenes have not been fully investigated. The neutral molecules of 3,3-diisopropyl-1-phenyltriazene and 1-(4-chlorophenyl)-3-cyclopentyltriazene in acetonitrile, the UV-visible spectra corresponded respectively to HOMO → LUMO transitions with a large maximum absorption at 299.74 nm (4.1364 eV) and 299.57 nm (4.1387 eV) and the most intense oscillator strength (f = 0.6988) and (f = 0.7372). These results suggest that the electronic transitions of the compounds are highly influenced by the nature of the substituents on the triazene unit, as well as the solvent used in the experiment. The redox couple 0.92 and -0.44 V/Ag/AgCl is attributed to the phenyl group. Compound III showed an oxidation and reduction peak respectively -0.27 and -0.8 V/Ag/AgCl attributed to the phenyl molecule. The study concluded that all three compounds were electroactive and exhibited reversible characteristics with oxidizing/reducing couples. This study aims to contribute to research on the optical properties of triazenes compounds and the application of quantum chemical calculation methods for understanding their molecular structures. By investigating the solute-solvent interactions occurring in the solvation shell of the solutes, we aim to gain insights into the effects of solvents on the UV-visible absorption spectrum of triazenes. Our findings may have implications for the development of functionalized triazenes as potential electrochromic materials.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) (Grant Nos.2018R1A6A1A03024334,2019R1A2C1007637,2021M3I3A1082880,2021R1I1A1A01044174)the Basic Science Research Capacity Enhancement Project through Korea Basic Science Institute (Grant No.2019R1A6C1010024)。
文摘The discovery of efficient,selective,and stable electrocatalysts can be a key point to produce the largescale chemical fuels via electrochemical CO_(2) reduction(ECR).In this study,an earth-abundant and nontoxic ZnO-based electrocatalyst was developed for use in gas-diffusion electrodes(GDE),and the effect of nitrogen(N)doping on the ECR activity of ZnO electrocatalysts was investigated.Initially,a ZnO nanosheet was prepared via the hydrothermal method,and nitridation was performed at different times to control the N-doping content.With an increase in the N-doping content,the morphological properties of the nanosheet changed significantly,namely,the 2D nanosheets transformed into irregularly shaped nanoparticles.Furthermore,the ECR performance of Zn O electrocatalysts with different N-doping content was assessed in 1.0 M KHCO_(3) electrolyte using a gas-diffusion electrode-based ECR cell.While the ECR activity increased after a small amount of N doping,it decreased for higher N doping content.Among them,the N:ZnO-1 h electrocatalysts showed the best CO selectivity,with a faradaic efficiency(FE_(CO))of 92.7%at-0.73 V vs.reversible hydrogen electrode(RHE),which was greater than that of an undoped Zn O electrocatalyst(FE_(CO)of 63.4%at-0.78 V_(RHE)).Also,the N:ZnO-1 h electrocatalyst exhibited outstanding durability for 16 h,with a partial current density of-92.1 mA cm^(-2).This improvement of N:ZnO-1 h electrocatalyst can be explained by density functional theory calculations,demonstrating that this improvement of N:ZnO-1 h electrocatalyst comes from(ⅰ)the optimized active sites lowering the free energy barrier for the rate-determining step(RDS),and(ⅱ)the modification of electronic structure enhancing the electron transfer rate by N doping.
基金The authors gratefully acknowledge the financial support of the Natural Science Foundation of China,China(Grant No.21975082 and 21736003)the Guangdong Basic and Applied Basic Research Foundation(Grant Number:2019A1515011472 and 2022A1515011341)the Science and Technology Program of Guangzhou(Grant Number:202102080479).
文摘In order to better understand the specific substituent effects on the electrochemical oxidation process of β-O-4 bond, a series of methoxyphenyl type β-O-4 dimer model compounds with different localized methoxyl groups, including 2-(2-methoxyphenoxy)-1-phenylethanone, 2-(2-methoxyphenoxy)-1-phenylethanol, 2-(2-methoxyphenoxy)-1-(4-methoxyphenyl)ethanone, 2-(2-methoxyphenoxy)-1-(4-methoxyphenyl)ethanol, 2-(2,6-dimethoxyphenoxy)-1-(4-methoxyphenyl)ethanone, 2-(2,6-dimethoxyphenoxy)-1-(4-methoxyphenyl)ethanol have been selected and their electrochemical properties have been studied experimentally by cyclic voltammetry, and FT-IR spectroelectrochemistry. Combining with electrolysis products distribution analysis and density functional theory calculations, oxidation mechanisms of all six model dimers have been explored. In particular, a total effect from substituents of both para-methoxy(on the aryl ring closing to Cα) and Cα-OH on the oxidation mechanisms has been clearly observed, showing a significant selectivity on the Cα-Cβbond cleavage induced by electrochemical oxidations.
基金funded by the National Natural Science Foundation of China(Nos.51801189)The Central Guidance on Local Science and Technology Development Fund of Shanxi Province(Nos.YDZJTSX2021A027)+2 种基金The National Natural Science Foundation of China(Nos.51801189)The Science and Technology Major Project of Shanxi Province(No.20191102008,20191102007)The North University of China Youth Academic Leader Project(No.11045505).
文摘This work studied the microstructure,mechanical properties and damping properties of Mg_(95.34)Ni_(2)Y_(2.66) and Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloys systematically.The difference in the evolution of the long-period stacked ordered(LPSO)phase in the two alloys during heat treatment was the focus.The morphology of the as-cast Mg_(95.34)Ni_(2)Y_(2.66)presented a disordered network.After heat treatment at 773 K for 2 hours,the eutectic phase was integrated into the matrix,and the LPSO phase maintained the 18R structure.As Zn partially replaced Ni,the crystal grains became rounded in the cast alloy,and lamellar LPSO phases and more solid solution atoms were contained in the matrix after heat treatment of the Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloy.Both Zn and the heat treatment had a significant effect on damping.Obvious dislocation internal friction peaks and grain boundary internal friction peaks were found after temperature-dependent damping of the Mg_(95.34)Ni_(2)Y_(2.66)and Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloys.After heat treatment,the dislocation peak was significantly increased,especially in the alloy Mg_(95.34)Ni_(2)Y_(2).66.The annealed Mg_(95.34)Ni_(2)Y_(2.66)alloy with a rod-shaped LPSO phase exhibited a good damping performance of 0.14 atε=10^(−3),which was due to the difference between the second phase and solid solution atom content.These factors also affected the dynamic modulus of the alloy.The results of this study will help in further development of high-damping magnesium alloys.
基金Natural Science Foundation of Jiangsu Province,Grant/Award Number:BK20210527National Natural Science Foundation of China,Grant/Award Number:42107158Training Program for Innovation and Entrepreneurship,China University of Mining and Technology。
文摘In recent years,the exploration of seabed has been intensified,but the submarine soils of silt and sand in the Yellow Sea area have not been well investigated so far.In this study,the physical and mechanical properties of silt and sand from the Yellow Sea were measured using a direct shear apparatus and their microstructures were observed using a scanning electron microscope.The test results suggest that the shear strength of silt and sand increases linearly with the increase of normal stress.Based on the direct shear test,the scanning electron microscope was used to observe the section surface of sand.It is observed that the section surface becomes rough,with many“V”‐shaped cracks.Many particles appear on the surface of the silt structure and tend to be disintegrated.The X‐ray diffraction experiment reveals that the sand and silt have different compositions.The shear strength of sand is slightly greater than that of silt under high stress,which is related to the shape of soil particles and the mineral composition.These results can be a reference for further study of other soils in the Yellow Sea;meanwhile,they can serve as soil parameters for the stability and durability analyses of offshore infrastructure construction.
文摘For the challenging nature of the zirconium environment analysis, this study consists to analyze the electrochemical behavior of Zirconium in both aqueous and organic media. To that end first the electrolytic media was selected on the basis of the Pourbaix potential-pH diagram, which provides informations on the predominance of Zr<sup>(IV) </sup> ion and Zr in aqueous media. In aqueous media, analyzes were first carried out in acidic media then in basic media. Studies have thus revealed that the acidic environment is not favourable for the electrochemical analysis of zirconium. Voltammograms obtained in an acidic environment show no zirconium detection signal;this is due to the strong presence of H<sup>+</sup> ions in the solution. We have also observed in acidic media the phenomenon of passivation of the electrode surface. In aqueous alkaline media (pH = 13), we have drawn in reduction several Intensity-Potential curves by fixingsome technical parameterslike scanning speed, rotation speed of the electrode. The obtained voltammograms show cathodic waves, starting from -1.5 V/DHW and attributed to the reduction of Zr<sup> (IV) </sup> to Zr (0). The last phase of this study focused on the electrochemical analysis of zirconium in an organic media. In this media, several intensity-potential curves were plotted in reduction and in cyclic voltammetry with various parameters. Through several reduction analysis, the Zr<sup> (IV) </sup> was reduced to Zr (0) to the potential of -1.5 V/DHW. The electrochemical analysis of zirconium in organic media seems globally easier to achieve thanks to its large solvent window (i.e. dimethylformamide (DMF) solvent window > 6 V).
基金Funded by the National Natural Science Foundation of China (Nos.51772033, 52002040)the National Key Research and Development Program of China (No. 2023YFB3711400)。
文摘The purpose of this research is to investigate the hydration behavior and cementitious properties of the mixture of calcium carbonate and aluminate, and to explore whether it can be adopted as a new low-carbon cementitious material. The composite system of calcium carbonate and aluminate minerals is studied by measuring the component of hydration products, the hydration heat, setting time and compressive strength.The results prove that the composite system has certain cementitious properties and is feasible to prepare new low-carbon cement.
基金Project supported by the National Natural Science Foundation of China (Grant No. 52088101)the Kunpeng Plan of Zhejiang ProvinceNingbo Top Talent Program。
文摘Saturation magnetization,magneto-crystalline anisotropy field,and dielectric properties are closely related to microwave devices applied at different frequencies.For regulating the magnetic and dielectric properties of W-type barium ferrites,single-phase BaMe_(2)Fe_(16)O_(27)(Me=Fe,Mn,Zn,Ni,Co) with different Me ions were synthesized by the high-temperature solid-state method.The saturation magnetization(Ms) range from 47.77 emu/g to 95.34 emu/g and the magnetic anisotropy field(H_a) range from 10700.60 Oe(1 Oe=79.5775 A·m^(-1)) to 13739.57 Oe,depending on the type of cation substitution in the hexagonal lattice.The dielectric permittivity and dielectric loss decrease with increasing frequency of the AC electric field in the low-frequency region,while they almost remain constant in the high-frequency region.The charac teristics of easy regulation and preparation make it a potential candidate for use in microwave device applications.
基金supported by the National Key Research and Development Program of China(2021YFC2103300)the National Natural Science Foundation of China(22078148)the Natural Science Foundation of Jiangsu Province(BK20220002).
文摘Dissolved oxygen(DO)usually refers to the amount of oxygen dissolved in water.In the environment,medicine,and fermentation industries,the DO level needs to be accurate and capable of online monitoring to guide the precise control of water quality,clinical treatment,and microbial metabolism.Compared with other analytical methods,the electrochemical strategy is superior in its fast response,low cost,high sensitivity,and portable device.However,an electrochemical DO sensor faces a trade-off between sensitivity and long-term stability,which strongly limits its practical applications.To solve this problem,various advanced nanomaterials have been proposed to promote detection performance owing to their excellent electrocatalysis,conductivity,and chemical stability.Therefore,in this review,we focus on the recent progress of advanced nanomaterial-based electrochemical DO sensors.Through the comparison of the working principles on the main analysis techniques toward DO,the advantages of the electrochemical method are discussed.Emphasis is placed on recently developed nanomaterials that exhibit special characteristics,including nanostructures and preparation routes,to benefit DO determination.Specifically,we also introduce some interesting research on the configuration design of the electrode and device,which is rarely introduced.Then,the different requirements of the electrochemical DO sensors in different application fields are included to provide brief guidance on the selection of appropriate nanomaterials.Finally,the main challenges are evaluated to propose future development prospects and detection strategies for nanomaterial-based electrochemical sensors.
基金financial support provided by Projects(no.2020CDJXZ001)the Fundamental Research Funds for the Central Universities+1 种基金the Technology Innovation and Application Development Special Project of Chongqing(Z20211350 and Z20211351)Scientific Research Project of Chongqing Ecological Environment Bureau(no.CQEE2022-STHBZZ118)。
文摘The application of Mg-based electrochemical energy storage materials in high performance supercapacitors is an essential step to promote the exploitation and utilization of magnesium resources in the field of energy storage.Unfortunately,the inherent chemical properties of magnesium lead to poor cycling stability and electrochemical reactivity,which seriously limit the application of Mg-based materials in supercapacitors.Herein,in this review,more than 70 research papers published in recent 10 years were collected and analyzed.Some representative research works were selected,and the results of various regulative strategies to improve the electrochemical performance of Mg-based materials were discussed.The effects of various regulative strategies(such as constructing nanostructures,synthesizing composites,defect engineering,and binder-free synthesis,etc.)on the electrochemical performance and their mechanism are demonstrated using spinelstructured MgX_(2)O_(4) and layered structured Mg-X-LDHs as examples.In addition,the application of magnesium oxide and magnesium hydroxide in electrode materials,MXene's solid spacers and hard templates are introduced.Finally,the challenges and outlooks of Mg-based electrochemical energy storage materials in high performance supercapacitors are also discussed.
基金China Scholarship Council,Grant/Award Number:201806950083Advanced Materials research program of the Zernike National Research CentreFaculty of Science and Engineering(FSE),University of Groningen。
文摘The development of lithium-sulfur(Li-S)batteries is hindered by the disadvantages of shuttling of polysulfides and the sluggish redox kinetics of the conversion of sulfur species during discharge and charge.Herein,the crystallinities of a titanium nitride(TiN)film on copper-embedded carbon nanofibers(Cu-CNFs)are regulated and the nanofibers are used as interlayers to resolve the aforementioned crucial issues.A low-crystalline TiN-coated Cu-CNF(L-TiN-Cu-CNF)interlayer is compared with its highly crystalline counterpart(H-TiN-Cu-CNFs).It is demonstrated that the L-TiN coating not only strengthens the chemical adsorption toward polysulfides but also greatly accelerates the electrochemical conversion of polysulfides.Due to robust carbon frameworks and enhanced kinetics,impressive highrate performance at 2 C(913 mAh g^(-1)based on sulfur)as well as remarkable cyclic stability up to 300 cycles(626 mAh g^(-1))with capacity retention of 46.5%is realized for L-TiN-Cu-CNF interlayer-configured Li-S batteries.Even under high loading(3.8 mg cm^(-2))of sulfur and relatively lean electrolyte(10μL electrolyte per milligram sulfur)conditions,the Li-S battery equipped with L-TiN-Cu-CNF interlayers delivers a high capacity of 1144 mAh g^(-1)with cathodic capacity of 4.25 mAh cm^(-2)at 0.1 C,providing a potential pathway toward the design of multifunctional interlayers for highly efficient Li-S batteries.
文摘The durability of reinforced concrete structures is greatly influenced by the corrosion of the reinforcement. In addition to air pollution related to the repair of corroded structures, chloride ions are the main factors of corrosion of reinforced concrete structures. This study aims to valorize a clay inhibitor against reinforcement corrosion in reinforced concrete. This clay (Attapulgite) was incorporated into reinforced concretes at different percentages of substitution of calcined attapulgite (0%, 5% and 10%) to cement in the formulation. The corrosion inhibitory power of attapulgite is evaluated in reinforced concretes subjected to the action of chloride ions at different intervals in the NaCl solution (1 day, 21 days and 45 days) by electrochemical methods (zero current chronopotentiometry, polarization curves and electrochemical impedance spectroscopy). This study showed that in the presence of chloride ions, the composition based on 10% attapulgite has an appreciable inhibitory effect with an average inhibitory efficiency of 82%.
基金The authors acknowledge support from the German Research Foundation(DFG:LE 2249/5-1)the Sino-German Center for Research Promotion(GZ1579)+1 种基金Yunnan Fundamental Research Projects(202201AW070014)Jiajia Qiu and Yu Duan appreciate support from the China Scholarship Council(No.201908530218&202206990027).
文摘Adopting a nano-and micro-structuring approach to fully unleashing the genuine potential of electrode active material benefits in-depth understandings and research progress toward higher energy density electrochemical energy stor-age devices at all technology readiness levels.Due to various challenging issues,especially limited stability,nano-and micro-structured(NMS)electrodes undergo fast electrochemical performance degradation.The emerging NMS scaffold design is a pivotal aspect of many electrodes as it endows them with both robustness and electrochemical performance enhancement,even though it only occupies comple-mentary and facilitating components for the main mechanism.However,extensive efforts are urgently needed toward optimizing the stereoscopic geometrical design of NMS scaffolds to minimize the volume ratio and maximize their functionality to fulfill the ever-increasing dependency and desire for energy power source supplies.This review will aim at highlighting these NMS scaffold design strategies,summariz-ing their corresponding strengths and challenges,and thereby outlining the potential solutions to resolve these challenges,design principles,and key perspectives for future research in this field.Therefore,this review will be one of the earliest reviews from this viewpoint.
基金financial supports provided by the China Scholarship Council(Nos.202206 290061 and 202206290062)。
文摘The laser powder bed fusion(LPBF) process can integrally form geometrically complex and high-performance metallic parts that have attracted much interest,especially in the molds industry.The appearance of the LPBF makes it possible to design and produce complex conformal cooling channel systems in molds.Thus,LPBF-processed tool steels have attracted more and more attention.The complex thermal history in the LPBF process makes the microstructural characteristics and properties different from those of conventional manufactured tool steels.This paper provides an overview of LPBF-processed tool steels by describing the physical phenomena,the microstructural characteristics,and the mechanical/thermal properties,including tensile properties,wear resistance,and thermal properties.The microstructural characteristics are presented through a multiscale perspective,ranging from densification,meso-structure,microstructure,substructure in grains,to nanoprecipitates.Finally,a summary of tool steels and their challenges and outlooks are introduced.
基金the financial support provided by the Australian Research Council(ARC)through the Future Fellowship(FT160100252)the Discovery Project(DP170102557)for this research。
文摘Magnesium(Mg)-based bone implants degrade rapidly in the physiological environment of the human body which affects their structural integrity and biocompatibility before adequate bone repair.Rare earth elements(REEs)have demonstrated their effectiveness in tailoring the corrosion and mechanical behavior of Mg alloys.This study methodically investigated the impacts of scandium(Sc)and terbium(Tb)in tailoring the corrosion resistance,mechanical properties,and biocompatibility of Mg–0.5Zn–0.35Zr–0.15Mn(MZZM)alloys fabricated via casting and hot extrusion.Results indicate that addition of Sc and Tb improved the strength of MZZM alloys via grain size reduction and solid solution strengthening mechanisms.The extruded MZZM–(1–2)Sc–(1–2)Tb(wt.%)alloys exhibit compressive strengths within the range of 336–405 MPa,surpassing the minimum required strength of 200 MPa for bone implants by a significant margin.Potentiodynamic polarization tests revealed low corrosion rates of as–cast MZZM(0.25 mm/y),MZZM–2Tb(0.45 mm/y),MZZM–1Sc–1Tb(0.18 mm/y),and MZZM–1Sc–2Tb(0.64 mm/y),and extruded MZZM(0.17 mm/y),MZZM–1Sc(0.15 mm/y),MZZM-2Sc(0.45 mm/y),MZZM-1Tb(0.17 mm/y),MZZM-2Tb(0.10 mm/y),MZZM–1Sc-1Tb(0.14 mm/y),MZZM-1Sc-2Tb(0.40 mm/y),and MZZM–2Sc–2Tb(0.51 mm/y)alloys,which were found lower compared to corrosion rate of high-purity Mg(~1.0 mm/y)reported in the literature.Furthermore,addition of Sc,or Tb,or Sc and Tb to MZZM alloys did not adversely affect the viability of SaOS2 cells,but enhanced their initial cell attachment,proliferation,and spreading shown via polygonal shapes and filipodia.This study emphasizes the benefits of incorporating Sc and Tb elements in MZZM alloys,as they effectively enhance corrosion resistance,mechanical properties,and biocompatibility simultaneously.