Transition metal selenides as sodium-ion hybrid capacitor(SIHC)anodes still suffer from amorphization difficulties and capacity degradation triggered by polyselenide dissolution.Herein,an atomistic amorphous strategy ...Transition metal selenides as sodium-ion hybrid capacitor(SIHC)anodes still suffer from amorphization difficulties and capacity degradation triggered by polyselenide dissolution.Herein,an atomistic amorphous strategy is proposed to construct adjacent Nb-Nb diatomic pairs with Se/O-coordination(Se4-Nb2-O2)in N-doped carbon-confined amorphous selenide clusters(a-Nb-Se/O@NC).Synergistic carbon confinement and hydrothermal oxygenation induce amorphization of Nb–Se bonds,eliminating crystalline rigidity while creating isotropic dual-ion transport channels and high-density active sites enriched with dangling bonds,thereby enhancing structural integrity and Na+storage capacity.The unique Se/O-coordinated Nb-Nb diatomic configuration establishes an electron-delocalized system,where the low electronegativity of Se counterbalances electron withdrawal from coordinated O at Nb centers.These strengthen d-p orbital hybridization,reduce Na+adsorption energy,and optimize charge transfer pathways and reaction kinetics in the amorphous clusters.Electrochemical tests reveal that the a-Nb-Se/O@NC anode delivers a high reversible capacity of 312.57 mAh g^(−1)and exceptional cyclic stability(103%capacity retention)after 5000 cycles at 10.0 A g^(−1).Assembled SIHCs achieve outstanding energy/power densities(207.1 Wh kg^(−1)/18966 W kg^(−1)),surpassing most amorphous and crystalline counterparts.This work provides methodological insights for the design of electrodes in high-power storage devices through atomic modulation and electronic optimization of amorphous selenides.展开更多
To develop novel β-type biomedical titanium alloys,a series of Ti-15Mo-xNb alloys（x=0,5,10 and 15,mass fraction in%） were designed and prepared by using vacuum arc melting method.The present study focused on the ef...To develop novel β-type biomedical titanium alloys,a series of Ti-15Mo-xNb alloys（x=0,5,10 and 15,mass fraction in%） were designed and prepared by using vacuum arc melting method.The present study focused on the effect of Nb addition on the microstructure,mechanical properties and castability of Ti-15 Mo alloy.Phase analysis and microstructure observation show that all the alloys consist of single β phase and the equiaxed β grain is refined with increasing Nb content.These β-type Ti-15Mo-xNb alloys exhibit good plasticity and rather low compression elastic modulus（in the range of 18.388-19.365 GPa）.After Nb addition,the compression yield strength of the alloys increases.With increasing Nb content,the micro-hardness of the alloys decreases.The alloys exhibit obvious fibrous strip microstructure after cold compression deformation.The castability test shows that the castability of the alloys after Nb addition decreases and that of the Ti-15 Mo alloy is the highest（92.01%）.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.52573299)the Natural Science Foundation of Jiangxi province(No.20242BAB25223,20232BCJ23025,20232BCJ25040,20232BAB214024)the Special Funding Program for Graduate Student Innovation of Jiangxi Province(No.YC2024-S594).
文摘Transition metal selenides as sodium-ion hybrid capacitor(SIHC)anodes still suffer from amorphization difficulties and capacity degradation triggered by polyselenide dissolution.Herein,an atomistic amorphous strategy is proposed to construct adjacent Nb-Nb diatomic pairs with Se/O-coordination(Se4-Nb2-O2)in N-doped carbon-confined amorphous selenide clusters(a-Nb-Se/O@NC).Synergistic carbon confinement and hydrothermal oxygenation induce amorphization of Nb–Se bonds,eliminating crystalline rigidity while creating isotropic dual-ion transport channels and high-density active sites enriched with dangling bonds,thereby enhancing structural integrity and Na+storage capacity.The unique Se/O-coordinated Nb-Nb diatomic configuration establishes an electron-delocalized system,where the low electronegativity of Se counterbalances electron withdrawal from coordinated O at Nb centers.These strengthen d-p orbital hybridization,reduce Na+adsorption energy,and optimize charge transfer pathways and reaction kinetics in the amorphous clusters.Electrochemical tests reveal that the a-Nb-Se/O@NC anode delivers a high reversible capacity of 312.57 mAh g^(−1)and exceptional cyclic stability(103%capacity retention)after 5000 cycles at 10.0 A g^(−1).Assembled SIHCs achieve outstanding energy/power densities(207.1 Wh kg^(−1)/18966 W kg^(−1)),surpassing most amorphous and crystalline counterparts.This work provides methodological insights for the design of electrodes in high-power storage devices through atomic modulation and electronic optimization of amorphous selenides.
基金Project(QN2010-04)supported by the Youth Startup Fund of the Second Affiliated Hospital of Harbin Medical University,ChinaProject(2010-156)supported by the Medical Scientific Research Foundation of Heilongjiang Province Health Department,ChinaProject(HIT.NSRIF.2012002)supported by the Fundamental Research Funds for the Central Universities,China
文摘To develop novel β-type biomedical titanium alloys,a series of Ti-15Mo-xNb alloys（x=0,5,10 and 15,mass fraction in%） were designed and prepared by using vacuum arc melting method.The present study focused on the effect of Nb addition on the microstructure,mechanical properties and castability of Ti-15 Mo alloy.Phase analysis and microstructure observation show that all the alloys consist of single β phase and the equiaxed β grain is refined with increasing Nb content.These β-type Ti-15Mo-xNb alloys exhibit good plasticity and rather low compression elastic modulus（in the range of 18.388-19.365 GPa）.After Nb addition,the compression yield strength of the alloys increases.With increasing Nb content,the micro-hardness of the alloys decreases.The alloys exhibit obvious fibrous strip microstructure after cold compression deformation.The castability test shows that the castability of the alloys after Nb addition decreases and that of the Ti-15 Mo alloy is the highest（92.01%）.
