查看更多>>摘要：This paper explores the potential of Longan peel waste(LPw)as a sustainable and cost-effective matrix for selenium-based cathodes in Li-Se and Na-Se batteries.Following activation,we created LP2—a designation for the carbon precursor derived from LPw,activated at a 1:2 ratio of carbonized LPw to KOH.This nomenclature,where'LP'stands for'Longan peel'and'2 reflects the optimization of this ratio,led to a hierarchical porous structure with an average pore size of 3.0307 nm and a significant BET surface area of 111.9386 m2 g-1.Selenium was incorporated into the LP2 matrix using a simple melt diffusion technique,yielding the composite Se@LP2.In Li-Se batteries,Se@LP2 exhibited an initial discharge capacity of 1033.75 mAh g-1 at 0.1C.At a 1C rate,the composite demonstrated a capacity retention of 301.14 mAh g-1 after 550 cycles and 380.91 mAh g-1 after 100 cycles.Moreover,for Na-Se batteries,the composite showcased a capacity retention of 347.18 mAh g-1 after 100 cycles at 0.1C.These findings underscore LP2's potential as a viable and efficient matrix for selenium-based cathodes,revealing promising prospects for the advancement of highly efficient Li-Se and Na-Se batteries.
查看更多>>摘要：Li metal batteries(LMBs)have attracted much attention due to the ultra-high theoretical capacity of the Li metal anode(LMA).However,the uncontrollable dendrites growth and low coulombic efficiency hinder their practical application.Here,we explore 3,5-difluoropyridine(2F-BD)as a novel electrolyte additive to enable high-performance LMBs.The 2F-BD additive participates in and modifies the solvation structure of Li ions by reducing the coordinated number of PF6-at the electrode surface,leading to the formation of a LiF and Li3N-rich solid electrolyte interphase(SEI).The LiF component increases the robustness of SEI and suppresses the formation of Li dendrites,while the Li3N component facilitates the transportation and reaction kinetics of Li ions.As a result,the Li||Li symmetric cell presents a stable cycling performance of up to 500 h at a current density of 1 mA cm-2.After coupling with LiFePO4 cathode,the obtained full cell achieves high specific capacities of 106.06 mA h g-1 and 84.98 mA h g-1 at 2.55 mA cm-2 and 5.10 mA cm-2,respectively,and maintains a high capacity retention of 84.0%after 1000 cycles at 0.13 mA cm-2,with an average cycling CE of 99.58%.
查看更多>>摘要：Thermal conductivity measurement of high-temperature heat transfer fluids provides a crucial basis for designing utility-scale thermal systems.Molten salts are promising heat transfer and thermal storage fluids in high-temperature thermal energy storage systems,while the molten salt thermal conductivity obtained in existing studies exhibits large deviations due to the high experimental complexity and unstandardized test procedures.In this work,we improve the conventional laser flash analysis method by proposing a theoretical heat transfer model for multi-layer heat conduction and providing a near-optimal molten salt container design.With water as a test sample,the relative error of thermal conductivity measurement using the improved method is 6.3%.The thermal conductivity of Solar Salt from 250 to 400 C,and of Hitec Salt from 160 to 250 C are measured and compared with the previous work.Both results show that the thermal conductivity increases with the temperature rising.This work will promote the technology standardization for accurately acquiring the thermal conductivity of molten salts or other similar high-temperature heat transfer fluids.
查看更多>>摘要：Controlled fabrication of materials by surface modification techniques has been a hot research topic.In this paper,one-dimensional(1D)core-shell structure Fe@Co nanowires(NWs)were successfully prepared by anchoring 0-dimensional(0D)Co nanoparticles on 1D Fe NWs based on the in situ reduction method.The electromagnetic parameters of the specimens at a filler mass fraction of 25 wt%were tested and the microwave loss mechanism was deeply analyzed.Binary magnetic metals in a core-shell structure have excellent multi-band microwave absorption capability(S-band,X-band and Ku-band).This is due to the heterogeneous interface and magnetic coupling effects tuning the dielectric and magnetic loss.This study offers a workable plan for creating effective multi-band magnetic metal-based microwave absorbers.
查看更多>>摘要：Electrochemical urea oxidation reaction(UOR)is a promising alternative to oxygen evolution reaction(OER)for realizing energy-saving hydrogen production.Developing efficient electrocatalysts for UOR becomes a central challenge.Recently,amorphous materials have been extensively used as UOR catalysts because of their numerous defective sites and flexible electronic properties.In this review,recent advancements in the development of amorphous UOR electrocatalysts are analyzed.The UOR mechanism is discussed,and the design of amorphous catalysts is then analyzed.The main catalyst design strategies are illustrated,including nanostructure control,heteroatom doping,composition regulation,and heterostructure construction.Also,electrocatalysts'structure-performance correlation is interpreted.Perspectives in this field are proposed for guiding future studies on the development of high-performance amorphous catalysts towards energy sustainability.
查看更多>>摘要：Equal channel angle pressing is recognized for its ability to refine alloy grains and alter grain orientation,thereby achieve better mechanical performance of the magnesium alloy.This study investigates the microstructures,dynamic recrystallization mechanism,texture development,and mechanical performance of GW94K(Mg-8.7Gd-4.18Y-0.42Zr wt.%)Mg alloy following ECAP-4 passes at 400 C and 3 mm/min.Results show that when high-temperature deformation is undertaken,twin formation is suppressed while dislocation slip is facili-tated,increasing dislocation density during deformation.Following ECAP deformation,the sample displayed higher fracture elongation,TYS,and UTS than the as-solutioned GW94K alloy.In particular,the GW94K alloy performed well mechanically after ECAP-4 passes,with an ultimate TYS of 231 MPa,an UTS of 290 MPa,and an elongation of 14.8%.DDRX and shear bands induce CDRX,both of which are important in plastic deformation.as well as in modifying microstructure and grain orientation during ECAP deformation.
查看更多>>摘要：Using nanocatalysts to catalyze water electrolysis for hydrogen production is an ideal solution to address the energy crisis.The most well-adopted fabrication methods for nanocatalysts are tube furnace annealing,Hydro-thermal method,etc.,hardly satisfying the trade-off among coarsening,dispersity,and particle size due to mutual restrictions.Herein,a universal,ultrafast and facile cellulose nanometer whiskers-high temperature shock(CNW-HTS)method was reported for fabricating a library of ultrafine metal nanoparticles with uniform dispersion and narrow size distribution.The metal-anchor functional groups in CNW(i.e.,-OH and-COOH)and the charac-teristics of the HTS method for ultrafast heating and powerful quenching synergistically contribute to the suc-cessful synthesis of metal nanoparticles.As an initial demonstration,the as-prepared Pt nanocatalyst(η10 mA cm-2=51.8 mV)shows more excellent catalytic hydrogen evolution reaction(HER)performance than the Pt catalyst prepared in the tubular furnace(η10 mA cm-2=169.4 mV).This rapid and universal CNW-HTS method can pave the way for nanomanufacturing to produce high-quality metal nanoparticles,thereby expanding ap-plications of energy conversion and electrocatalysis.
查看更多>>摘要：G115 martensitic steel is anticipated to be one of the preferred candidate materials in ultra-super critical(USC)power plants with steam temperatures above 650 C.Microstructure evolutions and mechanical properties of G115 martensitic steel after applying various heat treatment processes were investigated.The results demonstrate that the main precipitate in G115 martensitic steel after applying various heat treatment processes is M23C6 phase with Cr enrichment.The time required for M23C6 phase precipitation decreases with increasing secondary normalizing temperature and the extension in holding time according to its precipitation-temperature-time(PTT)curves.Volume fraction of M23C6 phase increases with increasing secondary normalizing temperature and holding time,which strengthens the inhibitory effect of precipitates on dislocations recovery and laths growth.Therefore,G115 martensitic steel can obtain the best mechanical properties after applying the highest secondary normalizing temperature and the longest holding time.In the current work,the excellent strength of G115 martensitic steel mainly derives from precipitates strengthening and laths strengthening.
查看更多>>摘要：To obtain a high-entropy alloy characterized by high strength and plasticity,(NiCoV)100-xGax(x=0,5,7)was successfully prepared,cold-rolled,and heat-treated.The microstructure was analyzed to correlate Ga content with the performance of the system.The addition of Ga can produce alloying effects,including solid solution strengthening effect,second phase precipitation strengthening effect,and layer misalignment energy reduction effect.The experimental results show adding Ga elements can enrich Ni,Co,V,and Ga above the grain bound-aries,causing the alloy to produce annealed twins inside.The alloy is strengthened mainly by precipitation,and the formation of the precipitation phase effectively enhances the strength of the alloy.The low stacking fault energy promotes the toughening of NiCoV but makes the plasticity of the alloy decrease.Still,the formation of annealed twins effectively increases the plasticity,which makes the alloy harder but does not reduce the plasticity too much.By comparing the experimental properties,(NiCoV)93Ga7 showed the best mechanical properties at the annealing temperature of 900 C,yield strength,tensile strength and elongation of 906 MPa,1321 MPa and 21.36%,respectively.
查看更多>>摘要：Defective NH2-UiO-66 adsorbent(named as NH2-UiO-66-SD)was successfully fabricated via post-synthesis method with the aid of both sodium carbonate anhydrous(Na2CO3)and diethylenetriaminepentaacetic acid(DTPA),in which the defective structure was confirmed by various characterizations.The as-obtained defective NH2-UiO-66-SD exhibited outstanding Pb(Ⅱ)sorption capacity(172.21 mg g-1)and rapid diffusion rate(29.87 mg g-1 min-0.5)at room temperature with optimal pH being 5.47.The Pb(Ⅱ)sorption behavior was conformed to pseudo-second-order kinetics and Langmuir model,demonstrating that the chemical sorption of the monolayer played a dominant model.As well,the thermodynamic parameters like standard Gibbs free energy change ΔGo(-31.21 kJ mol-1),standard enthalpy change ΔHo(12.79 kJ-1 mol-1)and standard entropy change ΔSo(146.73 J mol-1 K-1)revealed that the Pb(Ⅱ)sorption process of NH2-UiO-66-SD was spontaneous,endothermic and disordered.Furthermore,the NH2-UiO-66-SD exhibited desirable desorption and recirculation performances(removal efficiencies>85%in 5 runs)with ideal stability.Moreover,the Pb(Ⅱ)sorption mechanism of NH2-UiO-66-SD mainly included the electrostatic attractions and coordinative interactions.Overall,this work offered an intriguing method of fabricating defective NH2-UiO-66 adsorbent,which vastly enhanced adsorption efficiency for toxic metal ions elimination from wastewater.
NETL
NSTL
万方数据