Interfacial modulation of bifunctional electrolyte additive engineering for dendrite-free and robust lithium metal anode

Anode materials for rechargeable electric car batteries are obtained from Li-metal owing to their extremely high specific capacity and low redox potential.Unfortunately,safety concerns related to dendrite formation on the anode surface caused by the uneven distribution of Li-ions during the discharge process interfere with the use of Li-metal in industrial batteries.In this study,methyl vinyl sulfone(MVS),a sulfone-based functional electrolyte additive,is used in an additive engineering strategy to control Lielectrolyte interactions and address the aforementioned problems.Li dendrite growth may be restricted,and transition metal degradation on the surface of the cathode can be reduced by the MVS-derived functional electrolyte additive interfacial layer.The electrochemical performance of an ethylene carbonate/dimethyl carbonate(EC/DMC)+1 wt% MVS Li-metal anode of a Li||Li symmetric cell exhibits remarkable cycle stability,maintaining a low overvoltage for over 750 h at 1 mA cm^(-2),and capacity of 1 mA h cm^(-2).Additionally,LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811) full cells with the MVS additive exhibit enhanced electrochemical stability for 250 cycles at a current density of 100 mA g^(-1).This study provides an innovative approach for stabilizing the metal-electrolyte interfacial layer that may be used for practical applications in metal-based rechargeable batteries.

Evolution of nonmetallic inclusions in 80-t 9CrMoCoB large-scale ingots during electroslag remelting process

In combination with theoretical calculations,experiments were conducted to investigate the evolution behavior of nonmetallic inclusions(NMIs)during the manufacture of large-scale heat-resistant steel ingots using 9CrMoCoB heat-resistant steel and CaF_(2)–CaO–Al_(2)O_(3)–SiO_(2)–B_(2)O_(3)electroslag remelting(ESR)-type slag in an 80-t industrial ESR furnace.The main types of NMI in the consumable electrode comprised pure alumina,a multiphase oxide consisting of an Al_(2)O_(3)core and liquid CaO–Al_(2)O_(3)–SiO_(2)–MnO shell,and M_(23)C_(6)carbides with an MnS core.The Al_(2)O_(3)and MnS inclusions had higher precipitation temperatures than the M_(23)C_(6)-type carbide under equilibrium and nonequilibrium solidification processes.Therefore,inclusions can act as nucleation sites for carbide layer precipitation.The ESR process completely removed the liquid CaO–Al_(2)O_(3)–SiO_(2)–MnO oxide and MnS inclusion with a carbide shell,and only the Al_(2)O_(3)inclusions and Al_(2)O_(3)core with a carbide shell occupied the remelted ingot.The M_(23)C_(6)-type carbides in steel were determined as Cr_(23)C_(6)based on the analysis of transmission electron microscopy results.The substitution of Cr with W,Fe,or/and Mo in the Cr_(23)C_(6)lattice caused slight changes in the lattice parameter of the Cr_(23)C_(6)carbide.Therefore,Cr_(21.34)Fe_(1.66)C_(6),(Cr_(19)W_(4)C_(6),Cr_(18.4)Mo_(4.6)C_(6),and Cr_(16)Fe_(5)Mo_(2)C_(6)can match the fraction pattern of Cr_(23)C_(6)carbide.The Al_(2)O_(3)inclusions in the remelted ingot formed due to the reduction of CaO,SiO_(2),and MnO components in the liquid inclusion.The increased Al content in liquid steel or the higher supersaturation degree of Al_(2)O_(3)precipitation in the remelted ingot than that in the electrode can be attributed to the evaporation of CaF_(2)and the increase in CaO content in the ESR-type slag.

Effect of hafnium and molybdenum addition on inclusion characteristics in Co-based dual-phase high-entropy alloys

Specific grades of high-entropy alloys(HEAs)can provide opportunities for optimizing properties toward high-temperature applications.In this work,the Co-based HEA with a chemical composition of Co_(47.5)Cr_(30)Fe_(7.5)Mn_(7.5)Ni_(7.5)(at%)was chosen.The refractory metallic elements hafnium(Hf)and molybdenum(Mo)were added in small amounts(1.5at%)because of their well-known positive effects on high-temperature properties.Inclusion characteristics were comprehensively explored by using a two-dimensional cross-sectional method and extracted by using a three-dimensional electrolytic extraction method.The results revealed that the addition of Hf can reduce Al_(2)O_(3)inclusions and lead to the formation of more stable Hf-rich inclusions as the main phase.Mo addition cannot influence the inclusion type but could influence the inclusion characteristics by affecting the physical parameters of the HEA melt.The calculated coagulation coefficient and collision rate of Al_(2)O_(3)inclusions were higher than those of HfO_(2)inclusions,but the inclusion amount played a larger role in the agglomeration behavior of HfO_(2)and Al_(2)O_(3)inclusions.The impurity level and active elements in HEAs were the crucial factors affecting inclusion formation.

A triboelectric nanogenerator based on a spiral rotating shaft for efficient marine energy harvesting of the hydrostatic pressure differential

Equipment used in underwater sensing and exploration typically relies on cables or batteries for energy supply,resulting in a limited and inconvenient energy supply and marine environmental pollution that hinder the sustainable development of distributed ocean sensing networks.Here,we design a deep-sea differential-pressure triboelectric nanogenerator(DP-TENG)based on a spiral shaft drive using modified polymer materials to harness the hydrostatic pressure gradient energy at varying ocean depths to power underwater equipment.The spiral shaft structure converts a single compression into multiple rotations of the TENG rotor,achieving efficient conversion of differential pressure energy.The multi-pair electrode design enables the DP-TENG to generate a peak current of 61.7μA,the instantaneous current density can reach 0.69μA cm^(-2),and the output performance can be improved by optimizing the spiral angle of the shaft.The DP-TENG can charge a 33μF capacitor to 17.5 V within five working cycles.It can also power a digital calculator and light up 116 commercial power light-emitting diodes,demonstrating excellent output capability.With its simple structure,low production cost,and small form factor,the DP-TENG can be seamlessly integrated with underwater vehicles.The results hold broad prospects for underwater blue energy harvesting and are expected to contribute to the development of self-powered equipment toward emerging“smart ocean”and blue economy applications.

Microstructure and compressive deformation of hypereutectic Al-Si-Fe based P/M alloys fabricated by spark plasma sintering

Al-Si-Fe based alloys are attractive light-weight structural materials for automotive engine components because of their high wear resistance, low density and low thermal expansion. Al-17Si 5Fe-2Cu-lMg-lNi-lZr alloys were produced in compact form by a spark plasma sintering （SPS） technique using gas atomized powders. The mean grain size of the compact was 530 nm, and fine equiaxed grains and uniformly distributed precipitates were observed in the compact. The compressive deformation behavior of the SPSed materials was examined at various temperatures and strain rates. All the true stress-true strain curves showed steady state flow after reaching peak stress. The peak stress decreased with increasing test temperature and decreasing strain rate. In the deformed specimens, the equiaxed grain morphology and the dislocation microstructure within the equiaxed grains were observed. These facts strongly indicated the occurrence of dynamic recrystallization during high temperature deformation of the present alloy.

Towards a sustainable technology for production of extra-pure Ti metal:Electrolysis of sulfurized Ti(C,N)in molten CaCl_(2)

A new concept for producing highly pure Ti metal powder from ilmenite(FeTiO)_(3))is proposed in this article.Titanium nitride(TiN)or titanium oxycarbonitride(TiO_(x)C_(y)N_(z))could be synthesized in the first step via the simultaneous carbothermal reduction and nitridation(CTRN)of FeTiO3 to remove oxygen roughly.To separate oxygen completely,high-quality TiS2 samples were then synthesized from TiN and TiC using S2 gas,and the clean sulfides were finally reduced toα-Ti powders with spherical morphology using electrolysis in molten CaCl_(2).Xray diffraction(XRD),scanning electron microscopy(SEM)in conjunction with energy-dispersive X-ray spectroscopy(EDS),and elemental LECO analysis were used to study the phases and microstructures of the sulfides and the electrochemically reduced powders.The Ti powder showed no carbon contamination and consisted of high-purity foil-like Ti sheets with very low oxygen,carbon,and nitrogen contents of less than 0.15 wt%O,0.02 wt%C,and 0.003 wt%N,respectively.The quality of the Ti powder was much higher than that of the powder obtained using the conventional OS process(proposed by K.Ono and R.O.Suzuki)starting directly from the oxides.

First-principles calculation of phase equilibria and phase separation of the Fe-Ni alloy system

Theoretical investigation of the phase equilibria of the Fe-Ni alloy has been performed by combining the FLAPW total energy calculations and the Cluster Variation Method through the Cluster Expansion Method. The calculations have proved the stabilization of the LIE phase at 1：3 stoichiometry, which is in agreement with the experimental result, and predicted the existence of L1 0 as a stable phase below 550 K; this L1 0 phase has been missing in the conventional phase diagram. The calculations are extended to the Fe-rich region that is characterized by a wide range phase separation and has drawn considerable attention because of the intriguing Invar property associated with a Fe concentration of 65%. To reveal the origin of the phase separation, a P-V curve in an entire concentration range is derived by the second derivative of free energy functional of the disordered phase with respect to the volume. The calculation confirmed that the phase separation is caused by the breakdown of the mechanical-stability criterion. The newly calculated phase separation line combined with the L1 0 and L12Eorder-disordered phase boundaries provides phase equilibria in the wider concentration range of the system. Furthermore, a coefficient of thermal expansion （CTE） is attempted by incorporating the thermal vibration effect through harmonic approximation of the Debye-Gruneisen model. The Invar behavior has been reproduced, and the origin of this anomalous volume change has been discussed.

Fabrication and Mechanical Properties of Sm2O3 Doped CeO2 Reinforced Ti3AlC2 Nano Composite

The fabrication process of Sm2O3 doped CeO2 reinforced Ti3AlC2 nano composites including the nano particle dispersion process by a hetero-coagulation process was developed using in-situ synthesis and densification process of Ti3AlC2. The effects of Sm2O2 doped CeO2 nano particles on mechanical properties of Ti3AlC2 were investigated. It was found that the presence of 20SDC nano particles in Ti3AlC2 was very effective to improve the mechanical properties of Ti3AlC2 without spoiling the unique characteristics of Ti3AlC2temary carbide.

Formation of unidirectional nanoporous structures in thickly anodized aluminum oxide layer

A series of anodic aluminum oxide(AAO) was grown on the commercially pure 1050 aluminum sheet by controlling electrolyte temperature(2-15 ℃) and anodizing time(0.5-6 h),using a fixed applied current density of 3 A/dm2 in diluted sulfuric acid electrolyte.A crack-free thick AAO with the thickness of 105-120 μm and containing unidirectional nano sized pores(average pore diameter of 5-7 nm) is successfully achieved in the specimens anodized for 2 h,irrespective of electrolyte temperature.When anodizing time reaches 6 h,very thick AAO with the thickness of 230-284 μm is grown,and average diameter of unidirectional pores is in the range of 6-24 nm.The higher values in both the AAO thickness and pore diameter are attained for the specimens anodized at higher temperatures of 10-15 ℃.A crack is observed to exist in the AAO after anodizing up to 4 h and more.A higher fraction(more than 9%) of the crack is shown in the specimens anodized at higher temperatures of 10-15 ℃ for 6 h and a considerable amount of giant cracks are contained.

Fabrication of MoSi;coatings on molybdenum and its high-temperature anti-oxidation properties

Industrial spent MoSi_(2)-based materials were used to fabricate oxidation-resistant coatings on molybdenum via slurry painting in air. The microstructure, phase constituent and high-temperature oxidation behaviors of the coatings at 1500 ℃ were explored. The results show that the bonding layer is generated in the coatings after sintering,which strengthens the metallurgical combination between the coating and the substrate because of the formation of diffusion layers. Rare cracks appear in the coating using pure MoSi_(2)(PM coating) while the coating using spent MoSi_(2)(SM coating) is free of cracks due to decreased thermal expansion mismatch. After oxidation, the oxide scale of PM coating possesses large-sized pores while a relatively dense oxide scale is acquired by SM coating. Compared with PM coating, thinner glassy oxide scale with lower mass gain is obtained by SM coating, exhibiting better anti-oxidation properties at 1500 ℃.

Deviation of congruent composition in Fe-Pd system

The first-principles calculation of the disordered Ll0 phase boundary for the Fe-Pd system is attempted by combining the FLAPW electronic structure total energy calculations and the cluster variation method via the cluster expansion method. The lattice vibration effects are taken into account based on the Debye-Gruneisen model within quasi-harmonic approximation. The transition temperature is reproduced with very high accuracy. However, the experimental congruent composition of disordered L10 phase that significantly deviates from 1.＂ 1 stoichiometry is not reproduced. Fulther calculations are attempted based on the phenomenological Lennard-Jones type pair potential, which is capable of introducing both tetragonality of the Ll0 ordered phase and additional configurational freedom because of the magnetic spins. The prelimi- nary calculations indicate that the tetragonality enhances the stability of the L10 ordered phase and the magnetic contributions also change the transition temperature. Despite these findings, the shift of the congruent composition still remains as a subject that needs further research. The electronic origin of the shifting of the congruent composition is briefly discussed.

Changes in reaction time, coefficient of variance of reaction time, and autonomic nerve function in the mental fatigue state caused by long-term computerized Kraepelin test workload in healthy volunteers

Fatigue is a common sense caused by crushing labor, stressful social events and various illnesses. It is usually judged by their subjective symptoms, but it should be evaluated in an objective perspective. Here we show that the decrease of working efficiency and sympathetic hyperactivity are associated with mental fatigue state caused by prolonged mental workload. Recently we made a new mental fatigue model of healthy volunteers caused by long-term computerized Kraepelin test (CKT) workload. CKT is our new software for automatically checking the calculation capability, with which it is easy to determine the reaction time (RT), coefficient of variance of reaction time (CV), and accuracy of the answers (AC) during tasks. We put 24 healthy volunteers into the fatigue state by subjecting them to 120 minutes’ CKT workload, and then studied the changes in fatigue sensation, RT, CV, and AC before and after the CKT workload. The fatigue sensation, RT, and CV were clearly increased by the fatigue-inducing task and recovered during the resting period. We also studied the changes in autonomic nerve activity by using heart rate variability analysis. The low/high frequency component ratio (LF/HF) was signifi-cantly increased by the fatigue-inducing task and decreased by resting, suggesting that mental stress causes a relatively sympathetic nerve activity-dominant state. Therefore, our new fatigue model involving a long-term CKT workload is a good mental fatigue model to provide much information about the fatigue state simultane-ously, and the increase of RT, CV, and proportion of sympathetic activity (LF/HF) are associated with mental fatigue state. These might be useful objective biomarkers or evaluating a mental fatigue state.

Superconducting Electronics Research at CSIRO Australia——20 Years after Discovery of HTS

CSIRO has had a long-term research effort in superconductivity, in particular, since the discovery of HTS which promised big prospects. Significant progress has been made in research and development of HTS electronic devices and systems for practical applications such as mineral and exploration as well as some niche applications in emerging science and technology areas. This article presents an overview of the CSIRO research activities in HTS supercon- ducting electronics since 1987, outlining the HTS junction and device technology as well as various application systems developed by the group.

Effect of Water Vapor on the Oxidation of Pt-modified Ni-22Al Alloys

Cyclic oxidation behavior of two-phaseγ+γ'-Ni-22Al-5 and -10 Pt alloys in air with and without 30 vol.%H_2O at 1000℃was investigated.The oxidation of 5 and 10 Pt alloys in air was initially rapid and followed by a slow steady-state stage.The oxidation during this steady-state stage was followed the parabolic rate law,and the parabolic rate constants for the two different Pt content alloys were similar.However the mass change of 5 Pt alloy during the initial rapid oxidation stage was much higher than that of 10 Pt,and it resulted in higher oxidation mass gain on 5 Pt alloy after 500 cycles.Similar oxidation behavior,initial rapid followed by slow steady-state,was observed when the alloys were oxidized in air+30%H_2O,however the initial oxidation mass change in the wet atmosphere was much higher for both alloys than in air.Interestingly,the oxidation rate constants for both alloys during the steady-state stage significantly decreased in the atmosphere with water vapor.Particularly,oxidation mass gain on the 5 Pt alloy was not observed after about 100 cycles of oxidation.

Controlling cooperativity of a metastable open system coupled weakly to a noisy environment

The notion of cooperativity comprises a specific characteristic of a multipartite system concerning its ability to demonstrate a sigmoidal-type response of varying sensitivities to input stimuli in transitions between states under controlled conditions.From a statistical physics viewpoint,in this work we attempt to describe the cooperativity by the stability of a metastable open system with respect to irreversibility.To treat the evolution of a system weakly coupled to the environment in a kinetic framework,we consider two fluctuating energy levels of different dimensionalities,initial population of one level,reversible transitions of population between the levels,and irreversible depopulation of another level.An average is made over level fluctuations and environment vibrations so that an inter-level transition rate can be obtained accounting for the influences of external control on level position and dimensionality.It is found that the cooperativity of the two-level system is bounded approximately between 0.736 and unity,with the lower bound indicating worsening system stability.

Electrocatalytic and stoichiometric reactivity of 2D layered siloxene for high-energy-dense lithium-sulfur batteries

Lithium-sulfur batteries(LSBs)have emerged as promising power sources for high-performance devices such as electric vehicles.However,the poor energy density of LSBs owing to polysulfide shuttling and passivation has limited their further market penetration.To mitigate this challenge,two-dimensional(2D)siloxene(2DSi),a Si-based analog of graphene,is utilized as an additive for sulfur cathodes.The 2DSi is fabricated on a large scale by simple solvent extraction of calcium disilicide to form a thin-layered structure of Si planes functionalized with vertically aligned hydroxyl groups in the 2DSi.The stoichiometric reaction of 2DSi with polysulfides generates a thiosulfate redox mediator,secures the intercalation pathway,and reveals Lewis acidic sites within the siloxene galleries.The 2DSi utilizes the corresponding in-situ-formed electrocatalyst,the 2D confinement effect of the layered structure,and the surface affinity based on Lewis acid-base interaction to improve the energy density of 2DSi-based LSB cells.Combined with the commercial carbon-based current collector,2DSi-based LSB cells achieve a volumetric energy density of 612 Wh Lcell^(−1) at 1 mA cm^(−2) with minor degradation of 0.17%per cycle,which rivals those of state-of-the-art LSBs.This study presents a method for the industrial production of high-energy-dense LSBs.

Electrochemical Polymerization of 4,4-Dimethyl-2,2’-Bithiophene in Concentrated Polymer Liquid Crystal Solution

Electrochemical polymerization of 4,4’-dimethyl-2,2’-bithiophene (4DMBT) was carried out in a concentrated solution of hydroxypropyl cellulose (HPC) liquid crystal in N,N-dimethylformamide. Infrared absorption spectra suggested that the resultant polymer film contains HPC. This study demonstrates an electrochemical preparation of a polymer composite having liquid crystal order. We proposed a helical stacking composite model.

Rotation of Biological Cells:Fundamentals and Applications

Cell rotation is one of the most important techniques for cell manipulation in modern bioscience,as it not only permits cell observation from any arbitrary angle,but also simplifies the procedures for analyzing the mechanical properties of cells,characterizing cell physiology,and performing microsurgery.Numerous approaches have been reported for rotating cells in a wide range of academic and industrial applications.Among them,the most popular are micro-robot-based direct contact manipulation and field-based non-contact methods(e.g.,optical,magnetic,electric,acoustic,and hydrodynamic methods).This review first summarizes the fundamental mechanisms,merits,and demerits of these six main groups of approaches,and then discusses their differences and limitations in detail.We aim to bridge the gap between each method and illustrate the development progress,current advances,and prospects in the field of cell rotation.

Hexagonal Disk Structures Obtained during Carbonization of <i>Botryococcus braunii</i>Residues

In this study, we report a two-dimensional (2D) hexagonal disk obtained by carbonization of Botryococcus braunii (B. braunii) residues. Carbonization at 700℃followed by naturally cooling down to room temperature under a non-inert gas flow atmosphere affords to yield this unique structure. The 2D hexagonal disks consist of more than 52% carbon and more than 25% oxygen. Slight amount of Fe, silicon and magnesium would be the trigger of the formation of hexagonal structure. Treatment of biomass residue is a challenge in the near future accompanied by the achievement of new energy technology in the industrial level. This research points out that efficient use of discharged biomass residue could create a new avenue for material science. The morphology of obtained crystals carbonized in different conditions, especially with the existence of argon flow, was also investigated.

Formation of Hybrid Ring Structure of Cyanurate/Isocyanurate in the Reaction be-tween 2,4,6-Tris(4-Phenyl-Phenoxy)-1, 3,5-Triazine and Phenyl Glycidyl Ether

Reaction products of 2,4,6-tris(4-phenyl-phenoxy)-1,3,5-triazine derived from 4-phenylphenol cyanate ester and phenyl glycidyl ether were analyzed. In addition to an isocyanurate compound and an oxazolidone compound which were well known as reaction products of cyanate esters and epoxy resins, compounds with hybrid ring structure of cyanurate/isocyanurate were determined. Gibbs free energies of the compound having hybrid ring structure of cyanurate/isocyanurate with two isocyanurate moiety were found to be lower than that of the compound with cyanurate ring structure through calculations. Calculation data supported the existence of hybrid ring structure of cy-anurate/isocyanurate. It was revealed that isomerization from cyanurate to isocyanurate occurs via hybrid ring structure of cyanurate/isocyanurate in the reaction of aryl cyanurate and epoxy.