The effect of Cr2O3 on the nucleation and crystallization of Na2O-CaO-Al2O3-SiO2-F- glass has been investigated by means of ESR(Electron Spin Resonance), SEM(Scanning Electron Microscope), EDS(Energy Dispersive Specro...The effect of Cr2O3 on the nucleation and crystallization of Na2O-CaO-Al2O3-SiO2-F- glass has been investigated by means of ESR(Electron Spin Resonance), SEM(Scanning Electron Microscope), EDS(Energy Dispersive Specrometer) and so on. Computer pattern recognition is applied to optimize the heat-treatment schedules. The experimental results show that the base glass containing more than 1 .5 % (mass fraction) Cr2O3 can be nucleated internally and converted to spheroidal crystal glass materials. The spheroidal crystal consisted of fibrous wollastonite crystals radiating from a center. The residual glass phase filled in the interstices between the fibers and between the spherulites. During heat treatment process, the valence states ofchromium changed from Cr6- to Cr3-, and the Cr-spinel solidsolution [CaCr2O4] precipitated followed this valence change. At the primary stage of crystallization, the Cr-spinel could act as a nucleating center on which the principal or}stalline phase β-CaSiO3 grew epitaxially.展开更多
A series of 20Li_(2)O-30V_(2)O_(5)-(50-x)SiO_(2)-xB_(2)O_(3)(mol.%)(x=10,20,30,40)glasses were prepared by the traditional melt-quenching synthesis.The amorphous nature of the glasses was determined by XRD,DSC and TEM...A series of 20Li_(2)O-30V_(2)O_(5)-(50-x)SiO_(2)-xB_(2)O_(3)(mol.%)(x=10,20,30,40)glasses were prepared by the traditional melt-quenching synthesis.The amorphous nature of the glasses was determined by XRD,DSC and TEM investigations.FTIR measurement revealed the functional group of obtained glasses.And EDS results confirmed the presence and uniform distribution of elements in the glasses.20Li_(2)O-30V_(2)O_(5)-40SiO_(2)-10B_(2)O_(3)(LVSB10)sample with the highest V^(4+) ratio exhibited the best cycling capacity.In order to further improve cycling stability of LVSB10 sample,ball milling was employed to reduce the particle size.The ball milled LVSB10 sample(LVSB10-b)showed an improved first discharge capacity,cycling stability and rate capacity.EIS measurements showed that ball milling can effectively decrease charge transfer impedance and facilitate Li^(+) ion diffusion.This work provides a new way to explore a new type of cathode materials for lithium ion batteries.展开更多
基金Project(50974090)supported by the National Natural Science Foundation of ChinaProjects(JCYJ20140418182819155,JCYJ20130329113849606)supported by the Shenzhen Dedicated Funding of Strategic Emerging Industry Development Program,China
文摘The effect of Cr2O3 on the nucleation and crystallization of Na2O-CaO-Al2O3-SiO2-F- glass has been investigated by means of ESR(Electron Spin Resonance), SEM(Scanning Electron Microscope), EDS(Energy Dispersive Specrometer) and so on. Computer pattern recognition is applied to optimize the heat-treatment schedules. The experimental results show that the base glass containing more than 1 .5 % (mass fraction) Cr2O3 can be nucleated internally and converted to spheroidal crystal glass materials. The spheroidal crystal consisted of fibrous wollastonite crystals radiating from a center. The residual glass phase filled in the interstices between the fibers and between the spherulites. During heat treatment process, the valence states ofchromium changed from Cr6- to Cr3-, and the Cr-spinel solidsolution [CaCr2O4] precipitated followed this valence change. At the primary stage of crystallization, the Cr-spinel could act as a nucleating center on which the principal or}stalline phase β-CaSiO3 grew epitaxially.
基金financially supported by Shenzhen Basic Research Project Funds(JCYJ20170817161127616).
文摘A series of 20Li_(2)O-30V_(2)O_(5)-(50-x)SiO_(2)-xB_(2)O_(3)(mol.%)(x=10,20,30,40)glasses were prepared by the traditional melt-quenching synthesis.The amorphous nature of the glasses was determined by XRD,DSC and TEM investigations.FTIR measurement revealed the functional group of obtained glasses.And EDS results confirmed the presence and uniform distribution of elements in the glasses.20Li_(2)O-30V_(2)O_(5)-40SiO_(2)-10B_(2)O_(3)(LVSB10)sample with the highest V^(4+) ratio exhibited the best cycling capacity.In order to further improve cycling stability of LVSB10 sample,ball milling was employed to reduce the particle size.The ball milled LVSB10 sample(LVSB10-b)showed an improved first discharge capacity,cycling stability and rate capacity.EIS measurements showed that ball milling can effectively decrease charge transfer impedance and facilitate Li^(+) ion diffusion.This work provides a new way to explore a new type of cathode materials for lithium ion batteries.
