Hydrogen(H2)is an essential vector for freeing our societies from fossil fuels and effectively initiating the energy transition.Offering high energy density,hydrogen can be used for mobile,stationary,or industrial app...Hydrogen(H2)is an essential vector for freeing our societies from fossil fuels and effectively initiating the energy transition.Offering high energy density,hydrogen can be used for mobile,stationary,or industrial applications of all sizes.This perspective on the crucial role of hydrogen is shared by a growing number of countries worldwide(e.g.,China,Germany,Japan,Republic of Korea,Australia,and United States),which are publishing ambitious roadmaps for the development of hydrogen and fuel cell technologies,supported by substantial financial efforts.展开更多
The Li-Mg-N-H hydrogen storage system is a promising hydrogen storage material due to its moderate operation temperature,good reversibility,and relatively high capacity.In this work,the Li-Mg-N-H composite was directl...The Li-Mg-N-H hydrogen storage system is a promising hydrogen storage material due to its moderate operation temperature,good reversibility,and relatively high capacity.In this work,the Li-Mg-N-H composite was directly synthesized by reactive ball milling(RBM) of Li3N and Mg powder mixture with a molar ratio of 2:1 under hydrogen pressure of 9 MPa.More than 8.8 wt%hydrogen was absorbed during the RBM process.The phases and structural evolution during the in situ hydrogenation process were analyzed by means of in situ solidgas absorption and ex situ X-ray diffraction(XRD) measurements.It is determined that the hydrogenation can be divided into two steps,leading to mainly the formation of a lithium magnesium imide phase and a poorly crystallized amide phase,respectively.The H-cycling properties of the as-milled composite were determined by temperature-programmed dehydrogenation(TPD) method in a closed system.The onset dehydrogenation temperature was detected at 125℃,and it can reversibly desorb 3.1 wt% hydrogen under a hydrogen back pressure of 0.2 MPa.The structural evolution during dehydrogenation was further investigated by in situ XRD measurement.It is found that Mg(NH_(2))_(2)phase disappears at about 200 ℃,and Li_(2)Mg_(2)N_(3)H_(3),LiNH_(2),and Li_(2)MgN_(2)H_(2)phases coexist at even 300 ℃,revealing that the dehydrogenation process is step-wised and only partial hydrogen can be desorbed.展开更多
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文摘Hydrogen(H2)is an essential vector for freeing our societies from fossil fuels and effectively initiating the energy transition.Offering high energy density,hydrogen can be used for mobile,stationary,or industrial applications of all sizes.This perspective on the crucial role of hydrogen is shared by a growing number of countries worldwide(e.g.,China,Germany,Japan,Republic of Korea,Australia,and United States),which are publishing ambitious roadmaps for the development of hydrogen and fuel cell technologies,supported by substantial financial efforts.
基金financially supported by the Beijing Science and Technology Program(No.D141100002014002)the European COST Action(No.MP1103)
文摘The Li-Mg-N-H hydrogen storage system is a promising hydrogen storage material due to its moderate operation temperature,good reversibility,and relatively high capacity.In this work,the Li-Mg-N-H composite was directly synthesized by reactive ball milling(RBM) of Li3N and Mg powder mixture with a molar ratio of 2:1 under hydrogen pressure of 9 MPa.More than 8.8 wt%hydrogen was absorbed during the RBM process.The phases and structural evolution during the in situ hydrogenation process were analyzed by means of in situ solidgas absorption and ex situ X-ray diffraction(XRD) measurements.It is determined that the hydrogenation can be divided into two steps,leading to mainly the formation of a lithium magnesium imide phase and a poorly crystallized amide phase,respectively.The H-cycling properties of the as-milled composite were determined by temperature-programmed dehydrogenation(TPD) method in a closed system.The onset dehydrogenation temperature was detected at 125℃,and it can reversibly desorb 3.1 wt% hydrogen under a hydrogen back pressure of 0.2 MPa.The structural evolution during dehydrogenation was further investigated by in situ XRD measurement.It is found that Mg(NH_(2))_(2)phase disappears at about 200 ℃,and Li_(2)Mg_(2)N_(3)H_(3),LiNH_(2),and Li_(2)MgN_(2)H_(2)phases coexist at even 300 ℃,revealing that the dehydrogenation process is step-wised and only partial hydrogen can be desorbed.
