Nb and Ti-13 Nb powders were used for improving the surface of Ti6Al4 V alloy.The deposition of the powders was carried out at various laser powers.The scanning electron microscopy（SEM）-EDS and optical microscopy we...Nb and Ti-13 Nb powders were used for improving the surface of Ti6Al4 V alloy.The deposition of the powders was carried out at various laser powers.The scanning electron microscopy（SEM）-EDS and optical microscopy were used for characterization.X-ray diffractometer（XRD） was used for analyzing the elemental composition and phase constituents.The hardness,wear and corrosion properties were achieved.The corrosion and the wear behaviours of the deposited layers were studied in a Hanks solution（simulated body fluid,SBF）.The microstructures of Nb coatings reveal the presence of orthorhombic,dendritic α″ and metastable β-Nb phases which produce uneven hardness with an average of HV 364.For Ti-13 Nb coatings,martensitic α′ and metastable β-Nb phases with an average hardness of HV 423 were observed.The resistance of wear on dry sliding of Ti-13 Nb coating is attributed to the increase in hardness.Experimental results indicate that deposition of Nb and Ti-13 Nb on Ti6Al4 V grossly reduces the mass fractions of Al and V in all coatings.In SBF,Nb reinforcement produces the best coating that reveals the best wear and corrosion resistances as compared with the substrate.Hence,this coating will perform best for orthopaedic implant material enhancement.展开更多
Hydrogen energy has gained widespread recognition for its environmentally friendly nature,high energy density and abundant resources,making it a promising energy carrier for a sustainable and clean energy society.Howe...Hydrogen energy has gained widespread recognition for its environmentally friendly nature,high energy density and abundant resources,making it a promising energy carrier for a sustainable and clean energy society.However,safe and efficient hydrogen storage remains a significant challenge due to its inherent leakiness and flammability.To overcome these challenges,alloys featuring body-centered cubic(BCC)structures have emerged as compelling candidates for hydrogen storage,owing to their exceptional capacity to achieve high-density hydrogen storage up to 3.8 wt%at ambient temperatures.Nonetheless,their practical application faces limited dehydriding capacity,complex activation processes,high costs and poor cyclic stability.Various modification strategies have been explored to overcome these limitations,including lattice regulation,element substitution,rare earth doping and heat treatment.This progress report presents an overview of the previous advancements to enhance five crucial aspects(high-V,medium-V,low-V,V-free and high-entropy alloys)in composition design and hydrogen storage properties within BCC-structured alloys.Subsequently,an in-depth analysis is conducted to examine the relationship between crystal structures and hydrogen storage properties specific to BCC-structured alloys,covering aspects such as composition,crystal structure,hydrogen storage capacity,enthalpy and entropy.Furthermore,this review explores current challenges in this field and outlines directions for future research.These insights provide valuable guidance for the design of innovative and cost-effective hydrogen storage alloys.展开更多
V48Fe12Ti15Cr25 alloy was prepared using vacuum arc melting and was subsequently annealed for 10 h at 1273 K.The effects of annealing on the hydrogen storage properties and microstructure of the V48Fe12Ti15Cr25 alloys...V48Fe12Ti15Cr25 alloy was prepared using vacuum arc melting and was subsequently annealed for 10 h at 1273 K.The effects of annealing on the hydrogen storage properties and microstructure of the V48Fe12Ti15Cr25 alloys were investigated.The results indicated that the alloy consisted of main body-centered cubic,Ti-rich,and TiFe phases.After annealing,the kinetic properties of the alloy were improved but its hydrogen storage capacity was slightly reduced.The kinetic mechanisms of the hydrogen absorption and desorption of the alloys were studied.The dehydrogenation enthalpy of the alloy was decreased by 2.57 kJ/mol after annealing.Differential scanning calorimetry indicated that the hydride decomposition temperature of the annealed alloy was decreased.The hydrogen desorption activation energies of the as-cast and annealed alloys were calculated to be 79.41 and 71.25 kJ/mol,respectively.The results illustrated that annealing was a beneficial method of improving the kinetic and thermodynamic properties of the hydrogen absorption/desorption of the alloy.展开更多
The oxalate-phosphate polyanion-mixed cathode materials are promising for sodium-ion batteries(SIBs)due to their unique open-framework structures and high voltage property.However,materials of this type generally cont...The oxalate-phosphate polyanion-mixed cathode materials are promising for sodium-ion batteries(SIBs)due to their unique open-framework structures and high voltage property.However,materials of this type generally contain crystal water molecules in the lattice frameworks,which may affect their energy storage properties.This work aims to disclose the impacts of crystal water on physiochemical and electrochemical properties of Na_(2)(VO)_(2)(HPO_(4))_(2)(C_(2)O_(4))·2H_(2)O(NVPC-W).It shows that the water molecules can be eliminated by vacuum drying at 150°C.The elimination of water molecules does not change the crystal phase of the material,while the obtained Na_(2)(VO)_(2)(HPO_(4))_(2)(C_(2)O^(4))(NVPC)exhibits significant improvements in cycling stability,Coulombic efficiency,as well as rate performances.Kinetics analysis indicates that the existence of lattice water molecules hinders sodium-ion diffusion and promotes the degradation of electrodes.We believe the findings can help to develop high-performance cathode materials.展开更多
Crystal structure and some dynamic performances of Zi0.25V0.34Dy0.01Cr0.1Ni0.3 hydrogen storage electrode alloy have been investigated by XRD, FESEM-EDS, TEM and EIS measurements. The result shows that the alloy is ma...Crystal structure and some dynamic performances of Zi0.25V0.34Dy0.01Cr0.1Ni0.3 hydrogen storage electrode alloy have been investigated by XRD, FESEM-EDS, TEM and EIS measurements. The result shows that the alloy is mainly composed of V-based solid solution phase with body-centered-cubic structure and mono-crystal Ni3Ti phase with hexagonal structure （Space grope： P63/ mmc）, and it was first observed as TiNi-based secondary phase. The higher charge transfer resistance, higher apparent activation energy and lower hydrogen diffusion coefficient are reasons for the poor electrochemical activity of the dehydriding kinetics of Ti- V-Cr-Ni hydride alloy.展开更多
With the excessive consumption of nonrenewable resources,the exploration of effective and durable materials is highly sought after in the field of sustainable energy conversion and storage system.In this aspect,metalo...With the excessive consumption of nonrenewable resources,the exploration of effective and durable materials is highly sought after in the field of sustainable energy conversion and storage system.In this aspect,metalorganic frameworks(MOFs)are a new class of crystalline porous organicinorganic hybrid materials.MOFs have recently been gaining traction in energy-related fields.Owing to the coordination flexibility and multiple accessible oxidation states of vanadium ions or clusters,vanadium-MOFs(V-MOFs)possess unique structural characteristics and satisfactory electrochemical properties.Furthermore,V-MOFs-derived materials also exhibit superior electrical conductivity and stability when used as electrocatalysts and electrode materials.This review summarizes the research progress of V-MOFs(inclusive of pristine V-MOFs,V/M-MOFs,and POVbased MOFs)and their derivatives(vanadium oxides,carbon-coated vanadium oxide,vanadium phosphate,vanadate,and other vanadium doped nanomaterials)in electrochemical energy conversion(water splitting,oxygen reduction reaction)and energy storage(supercapacitor,rechargeable battery).Future possibilities and challenges for V-MOFs and their derivatives in terms of design and synthesis are discussed.Lastly,their applications in energy-related fields are also highlighted.展开更多
基金financially supported by the National Research Foundation of South AfricaThe National Laser Centre,CSIR,Pretoria,South Africa,is appreciated for laser facilitythe support from Tshwane University of Technology,South Africa
文摘Nb and Ti-13 Nb powders were used for improving the surface of Ti6Al4 V alloy.The deposition of the powders was carried out at various laser powers.The scanning electron microscopy（SEM）-EDS and optical microscopy were used for characterization.X-ray diffractometer（XRD） was used for analyzing the elemental composition and phase constituents.The hardness,wear and corrosion properties were achieved.The corrosion and the wear behaviours of the deposited layers were studied in a Hanks solution（simulated body fluid,SBF）.The microstructures of Nb coatings reveal the presence of orthorhombic,dendritic α″ and metastable β-Nb phases which produce uneven hardness with an average of HV 364.For Ti-13 Nb coatings,martensitic α′ and metastable β-Nb phases with an average hardness of HV 423 were observed.The resistance of wear on dry sliding of Ti-13 Nb coating is attributed to the increase in hardness.Experimental results indicate that deposition of Nb and Ti-13 Nb on Ti6Al4 V grossly reduces the mass fractions of Al and V in all coatings.In SBF,Nb reinforcement produces the best coating that reveals the best wear and corrosion resistances as compared with the substrate.Hence,this coating will perform best for orthopaedic implant material enhancement.
基金supported by the National Key R&D Program of China(No.2022YFB3504700)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA0400304)the Research Fund of Key Laboratory of Rare Earths,Chinese Academy of Sciences(No.E32PF00116).
文摘Hydrogen energy has gained widespread recognition for its environmentally friendly nature,high energy density and abundant resources,making it a promising energy carrier for a sustainable and clean energy society.However,safe and efficient hydrogen storage remains a significant challenge due to its inherent leakiness and flammability.To overcome these challenges,alloys featuring body-centered cubic(BCC)structures have emerged as compelling candidates for hydrogen storage,owing to their exceptional capacity to achieve high-density hydrogen storage up to 3.8 wt%at ambient temperatures.Nonetheless,their practical application faces limited dehydriding capacity,complex activation processes,high costs and poor cyclic stability.Various modification strategies have been explored to overcome these limitations,including lattice regulation,element substitution,rare earth doping and heat treatment.This progress report presents an overview of the previous advancements to enhance five crucial aspects(high-V,medium-V,low-V,V-free and high-entropy alloys)in composition design and hydrogen storage properties within BCC-structured alloys.Subsequently,an in-depth analysis is conducted to examine the relationship between crystal structures and hydrogen storage properties specific to BCC-structured alloys,covering aspects such as composition,crystal structure,hydrogen storage capacity,enthalpy and entropy.Furthermore,this review explores current challenges in this field and outlines directions for future research.These insights provide valuable guidance for the design of innovative and cost-effective hydrogen storage alloys.
基金National Natural Science Foundation of China(Grant No.51901105)Natural Science Foundation of Inner Mongolia,China(Grant Nos.2018LH05010,2019BS05005,and 2017BS0507).
文摘V48Fe12Ti15Cr25 alloy was prepared using vacuum arc melting and was subsequently annealed for 10 h at 1273 K.The effects of annealing on the hydrogen storage properties and microstructure of the V48Fe12Ti15Cr25 alloys were investigated.The results indicated that the alloy consisted of main body-centered cubic,Ti-rich,and TiFe phases.After annealing,the kinetic properties of the alloy were improved but its hydrogen storage capacity was slightly reduced.The kinetic mechanisms of the hydrogen absorption and desorption of the alloys were studied.The dehydrogenation enthalpy of the alloy was decreased by 2.57 kJ/mol after annealing.Differential scanning calorimetry indicated that the hydride decomposition temperature of the annealed alloy was decreased.The hydrogen desorption activation energies of the as-cast and annealed alloys were calculated to be 79.41 and 71.25 kJ/mol,respectively.The results illustrated that annealing was a beneficial method of improving the kinetic and thermodynamic properties of the hydrogen absorption/desorption of the alloy.
基金The authors thank the financial support from the National Key R&D Program of China(No.2019YFC1908301).
文摘The oxalate-phosphate polyanion-mixed cathode materials are promising for sodium-ion batteries(SIBs)due to their unique open-framework structures and high voltage property.However,materials of this type generally contain crystal water molecules in the lattice frameworks,which may affect their energy storage properties.This work aims to disclose the impacts of crystal water on physiochemical and electrochemical properties of Na_(2)(VO)_(2)(HPO_(4))_(2)(C_(2)O_(4))·2H_(2)O(NVPC-W).It shows that the water molecules can be eliminated by vacuum drying at 150°C.The elimination of water molecules does not change the crystal phase of the material,while the obtained Na_(2)(VO)_(2)(HPO_(4))_(2)(C_(2)O^(4))(NVPC)exhibits significant improvements in cycling stability,Coulombic efficiency,as well as rate performances.Kinetics analysis indicates that the existence of lattice water molecules hinders sodium-ion diffusion and promotes the degradation of electrodes.We believe the findings can help to develop high-performance cathode materials.
基金financially supported by the Doctoral Foundation of Yanshan University(No.B330)
文摘Crystal structure and some dynamic performances of Zi0.25V0.34Dy0.01Cr0.1Ni0.3 hydrogen storage electrode alloy have been investigated by XRD, FESEM-EDS, TEM and EIS measurements. The result shows that the alloy is mainly composed of V-based solid solution phase with body-centered-cubic structure and mono-crystal Ni3Ti phase with hexagonal structure （Space grope： P63/ mmc）, and it was first observed as TiNi-based secondary phase. The higher charge transfer resistance, higher apparent activation energy and lower hydrogen diffusion coefficient are reasons for the poor electrochemical activity of the dehydriding kinetics of Ti- V-Cr-Ni hydride alloy.
基金National Research Foundation of Singapore(NRF)Investigatorship,Grant/Award Number:NRF2016NRFNRFI001‐22National Natural Science Foundation of China,Grant/Award Numbers:51972067,22001021,51802044,51902062 and 5180204+3 种基金Guangdong Natural Science Funds for Distinguished Young Scholar,Grant/Award Number:2019B151502039Singapore MOE AcRF Tier 1,Grant/Award Number:2020‐T1‐001‐031Natural Science Foundation of Jiangsu Province,Grant/Award Number:BK20201048Natural Science Research Project of Higher Education Institutions in Jiangsu Province,Grant/Award Number:20KJB150008。
文摘With the excessive consumption of nonrenewable resources,the exploration of effective and durable materials is highly sought after in the field of sustainable energy conversion and storage system.In this aspect,metalorganic frameworks(MOFs)are a new class of crystalline porous organicinorganic hybrid materials.MOFs have recently been gaining traction in energy-related fields.Owing to the coordination flexibility and multiple accessible oxidation states of vanadium ions or clusters,vanadium-MOFs(V-MOFs)possess unique structural characteristics and satisfactory electrochemical properties.Furthermore,V-MOFs-derived materials also exhibit superior electrical conductivity and stability when used as electrocatalysts and electrode materials.This review summarizes the research progress of V-MOFs(inclusive of pristine V-MOFs,V/M-MOFs,and POVbased MOFs)and their derivatives(vanadium oxides,carbon-coated vanadium oxide,vanadium phosphate,vanadate,and other vanadium doped nanomaterials)in electrochemical energy conversion(water splitting,oxygen reduction reaction)and energy storage(supercapacitor,rechargeable battery).Future possibilities and challenges for V-MOFs and their derivatives in terms of design and synthesis are discussed.Lastly,their applications in energy-related fields are also highlighted.
