One prominent cathode material utilized in commercial sodium-ion batteries is the O3-type NaNi_(0.5)Mn_(0.5)O_(2).The application of this material is hindered by multistage phase transitions and insufficient air stabi...One prominent cathode material utilized in commercial sodium-ion batteries is the O3-type NaNi_(0.5)Mn_(0.5)O_(2).The application of this material is hindered by multistage phase transitions and insufficient air stability.In this study,an innovative O3-type NaNi_(0.5)Mn_(0.5)O_(2),derived from Ni-MOFs (referred to as M-NNMO),has been developed as a cathode material for sodium-ion batteries.The M-NNMO cathode exhibits a discharge specific capacity of 124 mAh·g^(-1)at a rate of0.1C within 2.0 to 4.0 V.Furthermore,this material demonstrates an impressive capacity retention of 75%after undergoing 100 cycles.Complex phase transitions can be inhibited and ion diffusion rates can be increased simultaneously by Ni-MOFs through the enhancement of transition metal-oxygen bonding and the rise n Na layer gap,which are in charge of the remarkable performance improvement.Importantly,the enhanced stability of the M-NNMO transition metal layer based on the uniquestructural properties of Ni-MOFs in air stability tests.This work will provide theoretical guidance to design sodiumion battery cathode materials with superior performance.展开更多
The effect of different extrusion parameters on the microstructure and mechanical properties of Mg-4Sm-3Gd-2Yb-0.5Zr(SGY2)alloy was investigated.It was observed that under different extrusion parameters,unDRXed grains...The effect of different extrusion parameters on the microstructure and mechanical properties of Mg-4Sm-3Gd-2Yb-0.5Zr(SGY2)alloy was investigated.It was observed that under different extrusion parameters,unDRXed grains of SGY2 alloy exhibited a pronounced basal plane texture,specifically<01.10>//ED,while the texture of DRXed grains was relatively dispersed.Under the condition of 420℃ and an extrusion ratio of 9.4(420℃-ER9.4),the basal plane texture intensity of unDRXed grains in SGY2 alloy was the highest.Furthermore,SGY2 alloy at different extrusion parameters exhibited recrystallization mechanisms mainly characterized by continuous dynamic recrystallization(CDRX),with some DRXed grains and deformed grains experiencing discontinuous dynamic recrystallization(DDRX).Additionally,at the 420℃-ER9.4,the second phase particles in the as-extruded SGY2 alloy were smaller in size and exhibited a dispersed distribution.Under this condition,a significant amount of dislocation accumulation,dislocation bypassing,and dislocation tangling phenomena were observed in the SGY2 alloy.The primary deformation mechanism of unDRXed grains in the SGY2 alloy at the 420℃-ER9.4 may involve prismatic plane,pyramidal plane,and pyramidal plane<c+a>slip,thereby activating a significant amount of dislocations.Compared to other extrusion conditions,this condition is more prone to activate non-basal plane slip.The as-extruded SGY2 alloy exhibited superior mechanical properties,with ultimate tensile strength(UTS)and yield strength(YS)of 332 MPa and 278 MPa,respectively.This is mainly attributed to the extremely fine grains,with many DRXed grains having grain sizes smaller than 1μm,and higher density grain boundaries produced under this condition.Additionally,the unDRXed grains contain a high density of dislocations with small Schmid factor(SF),thus effectively inhibiting basal plane slip and strengthening the alloy to some extent.Similarly,the increased presence of second phase particles will also contribute to strengthening the alloy matrix through precipitation hardening.展开更多
A high-strength magnesium alloy containing Yb was prepared through a simple hot extrusion process.The effect of Yb addition on dynamic precipitation,texture evolution,dynamic recrystallization mechanisms,deformation m...A high-strength magnesium alloy containing Yb was prepared through a simple hot extrusion process.The effect of Yb addition on dynamic precipitation,texture evolution,dynamic recrystallization mechanisms,deformation mechanisms,and strengthening mechanisms in as-extruded Mg-4 Sm-3 Gd(-2 Yb)-0.5 Zr(SGY0,SGY2)alloys was systematically investigated.The results indicated that the average grain size decreased from 4.17μm to 1.48μm with the addition of Yb.This extreme grain refinement greatly enhances the strength.The addition of Yb significantly facilitated the phase precipitation,but did not change the texture type.The non-dynamic recrystallized(un DRXed)grains exhibited a strong basal plane texture of<0110>parallel to the extrusion direction(ED),while the dynamic recrystallized(DRXed)grains showed a weaker rare earth texture,characterized by<1212>//ED.Moreover,the as-extruded SGY0 and SGY2 alloys predominantly undergo continuous dynamic recrystallization(CDRX),and some DRXed grains exhibit a discontinuous dynamic recrystallization mechanism(DDRX).In addition,the addition of Yb facilitates the activation of non-basal plane slip.The dislocation types in the as-extruded SGY0 and SGY2 alloys include(a),(c)and(c+a)dislocations.However,the SGY2 alloy exhibits a relatively high dislocation density,which contributes to the enhancement of the strength.Extreme grain refinement and the dispersion of nanoscale second-phase particles are key factors in increasing the strength.展开更多
Zr0.5Ti0.5O2(ZT) and Zr0.25Ti0.25Al0.5O2(ZTA) mixed oxides were prepared by co-precipitation method and characterized by low temperature adsorption-desorption,XRD and NH3-TPD. The activity of Pt/Zr0.5Ti0.5O2 and Pt/ Z...Zr0.5Ti0.5O2(ZT) and Zr0.25Ti0.25Al0.5O2(ZTA) mixed oxides were prepared by co-precipitation method and characterized by low temperature adsorption-desorption,XRD and NH3-TPD. The activity of Pt/Zr0.5Ti0.5O2 and Pt/ Zr0.5Ti0.5Al0.5O2 catalysts was evaluated using the simulated gases. The results show that ZTA samples exhibit higher specific surface area,larger pore volume and proper surface acidic amount and acidity in comparison with ZT. The results of the catalytic test indicate that Pt/ZT and Pt/ZTA catalysts exhibit excellent low-temperature catalytic activity and lower light-off temperatures of hydrocarbon,carbon monoxide and nitrogen oxides,especially better conversion for nitrogen oxides (NOx). The addition of Al2O3 into ZT enhanced the anti-aging property of Pt/ ZTA catalysts due to the excellent textural,structural,surface acidity and thermal stability.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.52164029,52074099 and 52464033)Natural Science Foundation of Hainan Province(Nos.221RC585,821MS0782,221MS048 and 221RC 1072)+1 种基金Hainan Province Science and Technology Special Fund(Nos.ZDYF2022GXJS004 and ZDYF2021GXJS028)Scientific Research Foundation of Hainan Tropical Ocean University(No.RHDRC202112)
文摘One prominent cathode material utilized in commercial sodium-ion batteries is the O3-type NaNi_(0.5)Mn_(0.5)O_(2).The application of this material is hindered by multistage phase transitions and insufficient air stability.In this study,an innovative O3-type NaNi_(0.5)Mn_(0.5)O_(2),derived from Ni-MOFs (referred to as M-NNMO),has been developed as a cathode material for sodium-ion batteries.The M-NNMO cathode exhibits a discharge specific capacity of 124 mAh·g^(-1)at a rate of0.1C within 2.0 to 4.0 V.Furthermore,this material demonstrates an impressive capacity retention of 75%after undergoing 100 cycles.Complex phase transitions can be inhibited and ion diffusion rates can be increased simultaneously by Ni-MOFs through the enhancement of transition metal-oxygen bonding and the rise n Na layer gap,which are in charge of the remarkable performance improvement.Importantly,the enhanced stability of the M-NNMO transition metal layer based on the uniquestructural properties of Ni-MOFs in air stability tests.This work will provide theoretical guidance to design sodiumion battery cathode materials with superior performance.
基金financially supported by the National Natural Science Foundation of China(No.52371108,52201119)Frontier Exploration Project of Longmen Laboratory,China(LMQYTSKT014).
文摘The effect of different extrusion parameters on the microstructure and mechanical properties of Mg-4Sm-3Gd-2Yb-0.5Zr(SGY2)alloy was investigated.It was observed that under different extrusion parameters,unDRXed grains of SGY2 alloy exhibited a pronounced basal plane texture,specifically<01.10>//ED,while the texture of DRXed grains was relatively dispersed.Under the condition of 420℃ and an extrusion ratio of 9.4(420℃-ER9.4),the basal plane texture intensity of unDRXed grains in SGY2 alloy was the highest.Furthermore,SGY2 alloy at different extrusion parameters exhibited recrystallization mechanisms mainly characterized by continuous dynamic recrystallization(CDRX),with some DRXed grains and deformed grains experiencing discontinuous dynamic recrystallization(DDRX).Additionally,at the 420℃-ER9.4,the second phase particles in the as-extruded SGY2 alloy were smaller in size and exhibited a dispersed distribution.Under this condition,a significant amount of dislocation accumulation,dislocation bypassing,and dislocation tangling phenomena were observed in the SGY2 alloy.The primary deformation mechanism of unDRXed grains in the SGY2 alloy at the 420℃-ER9.4 may involve prismatic plane,pyramidal plane,and pyramidal plane<c+a>slip,thereby activating a significant amount of dislocations.Compared to other extrusion conditions,this condition is more prone to activate non-basal plane slip.The as-extruded SGY2 alloy exhibited superior mechanical properties,with ultimate tensile strength(UTS)and yield strength(YS)of 332 MPa and 278 MPa,respectively.This is mainly attributed to the extremely fine grains,with many DRXed grains having grain sizes smaller than 1μm,and higher density grain boundaries produced under this condition.Additionally,the unDRXed grains contain a high density of dislocations with small Schmid factor(SF),thus effectively inhibiting basal plane slip and strengthening the alloy to some extent.Similarly,the increased presence of second phase particles will also contribute to strengthening the alloy matrix through precipitation hardening.
基金financially supported by the National Natural Science Foundation of China(No.52371108,52201119,52203295)Frontier Exploration Project of Longmen Laboratory,China(LMQYTSKT014)the Joint Fund of Henan Science and Technology R&D Plan of China(242103810056)。
文摘A high-strength magnesium alloy containing Yb was prepared through a simple hot extrusion process.The effect of Yb addition on dynamic precipitation,texture evolution,dynamic recrystallization mechanisms,deformation mechanisms,and strengthening mechanisms in as-extruded Mg-4 Sm-3 Gd(-2 Yb)-0.5 Zr(SGY0,SGY2)alloys was systematically investigated.The results indicated that the average grain size decreased from 4.17μm to 1.48μm with the addition of Yb.This extreme grain refinement greatly enhances the strength.The addition of Yb significantly facilitated the phase precipitation,but did not change the texture type.The non-dynamic recrystallized(un DRXed)grains exhibited a strong basal plane texture of<0110>parallel to the extrusion direction(ED),while the dynamic recrystallized(DRXed)grains showed a weaker rare earth texture,characterized by<1212>//ED.Moreover,the as-extruded SGY0 and SGY2 alloys predominantly undergo continuous dynamic recrystallization(CDRX),and some DRXed grains exhibit a discontinuous dynamic recrystallization mechanism(DDRX).In addition,the addition of Yb facilitates the activation of non-basal plane slip.The dislocation types in the as-extruded SGY0 and SGY2 alloys include(a),(c)and(c+a)dislocations.However,the SGY2 alloy exhibits a relatively high dislocation density,which contributes to the enhancement of the strength.Extreme grain refinement and the dispersion of nanoscale second-phase particles are key factors in increasing the strength.
文摘Zr0.5Ti0.5O2(ZT) and Zr0.25Ti0.25Al0.5O2(ZTA) mixed oxides were prepared by co-precipitation method and characterized by low temperature adsorption-desorption,XRD and NH3-TPD. The activity of Pt/Zr0.5Ti0.5O2 and Pt/ Zr0.5Ti0.5Al0.5O2 catalysts was evaluated using the simulated gases. The results show that ZTA samples exhibit higher specific surface area,larger pore volume and proper surface acidic amount and acidity in comparison with ZT. The results of the catalytic test indicate that Pt/ZT and Pt/ZTA catalysts exhibit excellent low-temperature catalytic activity and lower light-off temperatures of hydrocarbon,carbon monoxide and nitrogen oxides,especially better conversion for nitrogen oxides (NOx). The addition of Al2O3 into ZT enhanced the anti-aging property of Pt/ ZTA catalysts due to the excellent textural,structural,surface acidity and thermal stability.
