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Xin-lin Wang - One of the best experts on this subject based on the ideXlab platform.
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Influence of the substituting Ni with Fe on the cycle stabilities of as-cast and as-Quenched La0.7Mg0.3Co0.45Ni2.55 − xFex (x = 0–0.4) electrode Alloys
Materials Characterization, 2010Co-Authors: Yanghuan Zhang, Rafi-ud-din, Hui-ping Ren, Shi-hai Guo, Xin-lin WangAbstract:The electrode Alloys La{sub 0.7}Mg{sub 0.3}Co{sub 0.45}Ni{sub 2.55-x}Fe{sub x} (x = 0, 0.1, 0.2, 0.3, 0.4) are fabricated by casting and rapid quenching techniques. The effects of the substitution of Fe for Ni on the cycle stabilities as well as the structures of the Alloys have been investigated thoroughly. The results indicate that the substitution of Fe for Ni significantly enhances the cycle stability of the Alloys. Furthermore, the positive impact of such substitution on the cycle stability has been observed to be more pronounced for the as-Quenched Alloy as compared to that for the as-cast one. Scanning electron microscopy (SEM) studies demonstrate that all the Alloys exhibit a multiphase structure comprising of two major phases (La, Mg)Ni{sub 3} and LaNi{sub 5} along with a residual phase of LaNi{sub 2}. The substitution of Fe for Ni has been observed to facilitate the formation of a like amorphous structure in the as-Quenched Alloy. With an increase in Fe contents, a significant grain refinement of the as-Quenched Alloy and an obvious enlargement in the lattice constants and the cell volumes of the Alloys have been noticed.
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Investigation on the structures and electrochemical performances of La0.75−xZrxMg0.25Ni3.2Co0.2Al0.1 (x = 0–0.2) electrode Alloys prepared by melt spinning
Journal of Alloys and Compounds, 2009Co-Authors: Yanghuan Zhang, Hui-ping Ren, Shi-hai Guo, Xin-lin WangAbstract:Abstract In order to improve the electrochemical cycle stability of the La–Mg–Ni system A 2 B 7 -type electrode Alloys, La in the Alloy was partially substituted by Zr and the melt-spinning technology was used for preparing La 0.75− x Zr x Mg 0.25 Ni 3.2 Co 0.2 Al 0.1 ( x = 0, 0.05, 0.1, 0.15, 0.2) electrode Alloys. The microstructures and electrochemical performances of the as-cast and Quenched Alloys were investigated in detail. The results obtained by XRD, SEM and TEM showed that the as-cast and Quenched Alloys have a multiphase structure which is composed of two main phases (La, Mg)Ni 3 and LaNi 5 as well as a residual phase LaNi 2 . The substitution of Zr for La leads to an obvious increase of the LaNi 5 phase in the Alloys, and it also helps the formation of a like amorphous structure in the as-Quenched Alloy. The results of the electrochemical measurement indicated that the substitution of Zr for La obviously decreased the discharge capacity of the as-cast and Quenched Alloys, but it significantly improved their cycle stability. The discharge capacity of the Alloys ( x ≤ 0.1) first increased and then decreased with the variety of the quenching rate. The cycle stability of the Alloys monotonously rose with increasing quenching rate.
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Effects of the substitution of Al for Ni on the structure and electrochemical performance of La0.7Mg0.3Ni2.55 − xCo0.45Alx (x = 0–0.4) electrode Alloys
Journal of Materials Science, 2007Co-Authors: Yanghuan Zhang, Hui-ping Ren, Shi-hai Guo, Dongliang Zhao, Xin-lin WangAbstract:In order to improve the cycling stability of La–Mg–Ni system (PuNi3-type) hydrogen storage Alloy, Ni in the Alloy was partially substituted by Al, and La0.7Mg0.3Ni2.55 − xCo0.45Alx (x = 0, 0.1, 0.2, 0.3, 0.4) electrode Alloys were prepared by casting and rapid quenching. The effects of the substitution of Al for Ni on the structure and electrochemical performance of the as-cast and Quenched Alloys were investigated in detail. The results obtained by XRD, SEM and TEM show that the substitution of Al for Ni has an inappreciable influence on the abundance of the LaNi2 phase in the as-Quenched Alloy, while it increases the amount of the LaNi2 phase in the as-cast Alloys. In addition, the substitution of Al for Ni is unfavourable for the formation of an amorphous in the as-Quenched Alloy. The results obtained by the electrochemical measurement indicate that the cycling stabilities of the as-cast and Quenched Alloys are significantly ameliorated with increasing Al content. When Al content increases from 0 to 0.4, the cycle life of the as-cast and Quenched (30 m/s) Alloys enhances from 72 to 132 cycles and from 100 to 136 cycles, respectively.
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Influences of the substitution of Fe for Ni on structures and electrochemical performances of the as-cast and Quenched La0.7Mg0.3Co0.45Ni2.55−xFex (x = 0–0.4) electrode Alloys
Journal of Alloys and Compounds, 2007Co-Authors: Yanghuan Zhang, Hui-ping Ren, Xiao-ping Dong, Xin-lin WangAbstract:Abstract In order to improve the cycle stability of the La–Mg–Ni system PuNi 3 -type hydrogen storage electrode Alloys, Ni in the Alloy was partially substituted by Fe. The La 0.7 Mg 0.3 Co 0.45 Ni 2.55− x Fe x ( x = 0, 0.1, 0.2, 0.3, 0.4) hydrogen storage Alloys were prepared by casting and rapid quenching. The effects of the substitution of Fe for Ni on the structures and electrochemical performances of the as-cast and Quenched Alloys were investigated in detail. The results of the electrochemical measurement indicate that the substitution of Fe for Ni obviously decreases the discharge capacity, high rate discharge capability (HRD) and discharge potential of the as-cast and Quenched Alloys, but it significantly improves their cycle stabilities, and its positive impact on the cycle life of as-Quenched Alloy is much more significant than on that of the as-cast one. The microstructure of the Alloys analyzed by XRD, SEM and TEM show that the as-cast and Quenched Alloys have a multiphase structure which is composed of two major phases (La, Mg)Ni 3 and LaNi 5 as well as a residual phase LaNi 2 . The substitution of Fe for Ni helps the formation of a like amorphous structure in the as-Quenched Alloy. With the increase of Fe content, the grain sizes of the as-Quenched Alloys significantly reduce, and the lattice constants and cell volumes of the Alloys obviously increase.
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Cycle stabilities of the La0.7Mg0.3Ni2.55−xCo0.45Mx (M = Fe, Mn, Al; x = 0, 0.1) electrode Alloys prepared by casting and rapid quenching
Journal of Alloys and Compounds, 2007Co-Authors: Yanghuan Zhang, Hui-ping Ren, Xiao-ping Dong, Ying Cai, Xin-lin WangAbstract:Abstract In order to improve the cycle stability of La–Mg–Ni system (PuNi 3 -type) hydrogen storage Alloy, Ni in the Alloy was partly substituted by Fe, Mn and Al, and the electrode Alloys La 0.7 Mg 0.3 Ni 2.55− x Co 0.45 M x (M = Fe, Mn, Al; x = 0, 0.1) were prepared by casting and rapid quenching. The effects of the substitution of Fe, Mn and Al for Ni and rapid quenching on the microstructures and electrochemical properties of the Alloys were investigated in detail. The results obtained by XRD, SEM and TEM indicate that element substitution has no influence on the phase compositions of the Alloys, but it changes the phase abundances of the Alloys. Particularly, the substitution of Al and Mn obviously raises the amount of the LaNi 2 phase. The substitution of Al and Fe leads to a significant refinement of the as-Quenched Alloy's grains. The substitution of Al strongly restrains the formation of an amorphous in the as-Quenched Alloy, but the substitution of Fe is quite helpful for the formation of an amorphous phase. The effects of the substitution of Fe, Mn and Al on the cycle stabilities of the as-cast and Quenched Alloys are different. The positive influence of the substitution elements on the cycle stabilities of the as-cast Alloys is in proper order Al > Fe > Mn, and for as-Quenched Alloys, the order is Fe > Al > Mn. Rapid quenching engenders an inappreciable influence on the phase composition, but it markedly enhances the cycle stabilities of the Alloys.
Yanghuan Zhang - One of the best experts on this subject based on the ideXlab platform.
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Influence of the substituting Ni with Fe on the cycle stabilities of as-cast and as-Quenched La0.7Mg0.3Co0.45Ni2.55 − xFex (x = 0–0.4) electrode Alloys
Materials Characterization, 2010Co-Authors: Yanghuan Zhang, Rafi-ud-din, Hui-ping Ren, Shi-hai Guo, Xin-lin WangAbstract:The electrode Alloys La{sub 0.7}Mg{sub 0.3}Co{sub 0.45}Ni{sub 2.55-x}Fe{sub x} (x = 0, 0.1, 0.2, 0.3, 0.4) are fabricated by casting and rapid quenching techniques. The effects of the substitution of Fe for Ni on the cycle stabilities as well as the structures of the Alloys have been investigated thoroughly. The results indicate that the substitution of Fe for Ni significantly enhances the cycle stability of the Alloys. Furthermore, the positive impact of such substitution on the cycle stability has been observed to be more pronounced for the as-Quenched Alloy as compared to that for the as-cast one. Scanning electron microscopy (SEM) studies demonstrate that all the Alloys exhibit a multiphase structure comprising of two major phases (La, Mg)Ni{sub 3} and LaNi{sub 5} along with a residual phase of LaNi{sub 2}. The substitution of Fe for Ni has been observed to facilitate the formation of a like amorphous structure in the as-Quenched Alloy. With an increase in Fe contents, a significant grain refinement of the as-Quenched Alloy and an obvious enlargement in the lattice constants and the cell volumes of the Alloys have been noticed.
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Investigation on the structures and electrochemical performances of La0.75−xZrxMg0.25Ni3.2Co0.2Al0.1 (x = 0–0.2) electrode Alloys prepared by melt spinning
Journal of Alloys and Compounds, 2009Co-Authors: Yanghuan Zhang, Hui-ping Ren, Shi-hai Guo, Xin-lin WangAbstract:Abstract In order to improve the electrochemical cycle stability of the La–Mg–Ni system A 2 B 7 -type electrode Alloys, La in the Alloy was partially substituted by Zr and the melt-spinning technology was used for preparing La 0.75− x Zr x Mg 0.25 Ni 3.2 Co 0.2 Al 0.1 ( x = 0, 0.05, 0.1, 0.15, 0.2) electrode Alloys. The microstructures and electrochemical performances of the as-cast and Quenched Alloys were investigated in detail. The results obtained by XRD, SEM and TEM showed that the as-cast and Quenched Alloys have a multiphase structure which is composed of two main phases (La, Mg)Ni 3 and LaNi 5 as well as a residual phase LaNi 2 . The substitution of Zr for La leads to an obvious increase of the LaNi 5 phase in the Alloys, and it also helps the formation of a like amorphous structure in the as-Quenched Alloy. The results of the electrochemical measurement indicated that the substitution of Zr for La obviously decreased the discharge capacity of the as-cast and Quenched Alloys, but it significantly improved their cycle stability. The discharge capacity of the Alloys ( x ≤ 0.1) first increased and then decreased with the variety of the quenching rate. The cycle stability of the Alloys monotonously rose with increasing quenching rate.
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Effects of the substitution of Al for Ni on the structure and electrochemical performance of La0.7Mg0.3Ni2.55 − xCo0.45Alx (x = 0–0.4) electrode Alloys
Journal of Materials Science, 2007Co-Authors: Yanghuan Zhang, Hui-ping Ren, Shi-hai Guo, Dongliang Zhao, Xin-lin WangAbstract:In order to improve the cycling stability of La–Mg–Ni system (PuNi3-type) hydrogen storage Alloy, Ni in the Alloy was partially substituted by Al, and La0.7Mg0.3Ni2.55 − xCo0.45Alx (x = 0, 0.1, 0.2, 0.3, 0.4) electrode Alloys were prepared by casting and rapid quenching. The effects of the substitution of Al for Ni on the structure and electrochemical performance of the as-cast and Quenched Alloys were investigated in detail. The results obtained by XRD, SEM and TEM show that the substitution of Al for Ni has an inappreciable influence on the abundance of the LaNi2 phase in the as-Quenched Alloy, while it increases the amount of the LaNi2 phase in the as-cast Alloys. In addition, the substitution of Al for Ni is unfavourable for the formation of an amorphous in the as-Quenched Alloy. The results obtained by the electrochemical measurement indicate that the cycling stabilities of the as-cast and Quenched Alloys are significantly ameliorated with increasing Al content. When Al content increases from 0 to 0.4, the cycle life of the as-cast and Quenched (30 m/s) Alloys enhances from 72 to 132 cycles and from 100 to 136 cycles, respectively.
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Influences of the substitution of Fe for Ni on structures and electrochemical performances of the as-cast and Quenched La0.7Mg0.3Co0.45Ni2.55−xFex (x = 0–0.4) electrode Alloys
Journal of Alloys and Compounds, 2007Co-Authors: Yanghuan Zhang, Hui-ping Ren, Xiao-ping Dong, Xin-lin WangAbstract:Abstract In order to improve the cycle stability of the La–Mg–Ni system PuNi 3 -type hydrogen storage electrode Alloys, Ni in the Alloy was partially substituted by Fe. The La 0.7 Mg 0.3 Co 0.45 Ni 2.55− x Fe x ( x = 0, 0.1, 0.2, 0.3, 0.4) hydrogen storage Alloys were prepared by casting and rapid quenching. The effects of the substitution of Fe for Ni on the structures and electrochemical performances of the as-cast and Quenched Alloys were investigated in detail. The results of the electrochemical measurement indicate that the substitution of Fe for Ni obviously decreases the discharge capacity, high rate discharge capability (HRD) and discharge potential of the as-cast and Quenched Alloys, but it significantly improves their cycle stabilities, and its positive impact on the cycle life of as-Quenched Alloy is much more significant than on that of the as-cast one. The microstructure of the Alloys analyzed by XRD, SEM and TEM show that the as-cast and Quenched Alloys have a multiphase structure which is composed of two major phases (La, Mg)Ni 3 and LaNi 5 as well as a residual phase LaNi 2 . The substitution of Fe for Ni helps the formation of a like amorphous structure in the as-Quenched Alloy. With the increase of Fe content, the grain sizes of the as-Quenched Alloys significantly reduce, and the lattice constants and cell volumes of the Alloys obviously increase.
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Cycle stabilities of the La0.7Mg0.3Ni2.55−xCo0.45Mx (M = Fe, Mn, Al; x = 0, 0.1) electrode Alloys prepared by casting and rapid quenching
Journal of Alloys and Compounds, 2007Co-Authors: Yanghuan Zhang, Hui-ping Ren, Xiao-ping Dong, Ying Cai, Xin-lin WangAbstract:Abstract In order to improve the cycle stability of La–Mg–Ni system (PuNi 3 -type) hydrogen storage Alloy, Ni in the Alloy was partly substituted by Fe, Mn and Al, and the electrode Alloys La 0.7 Mg 0.3 Ni 2.55− x Co 0.45 M x (M = Fe, Mn, Al; x = 0, 0.1) were prepared by casting and rapid quenching. The effects of the substitution of Fe, Mn and Al for Ni and rapid quenching on the microstructures and electrochemical properties of the Alloys were investigated in detail. The results obtained by XRD, SEM and TEM indicate that element substitution has no influence on the phase compositions of the Alloys, but it changes the phase abundances of the Alloys. Particularly, the substitution of Al and Mn obviously raises the amount of the LaNi 2 phase. The substitution of Al and Fe leads to a significant refinement of the as-Quenched Alloy's grains. The substitution of Al strongly restrains the formation of an amorphous in the as-Quenched Alloy, but the substitution of Fe is quite helpful for the formation of an amorphous phase. The effects of the substitution of Fe, Mn and Al on the cycle stabilities of the as-cast and Quenched Alloys are different. The positive influence of the substitution elements on the cycle stabilities of the as-cast Alloys is in proper order Al > Fe > Mn, and for as-Quenched Alloys, the order is Fe > Al > Mn. Rapid quenching engenders an inappreciable influence on the phase composition, but it markedly enhances the cycle stabilities of the Alloys.
Baoning Zong - One of the best experts on this subject based on the ideXlab platform.
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structural and catalytic properties of skeletal ni catalyst prepared from the rapidly Quenched ni50al50 Alloy
Journal of Catalysis, 2004Co-Authors: Minghua Qiao, Kangnian Fan, Baoning Zong, Shuai Wang, Xiaoxin ZhangAbstract:Abstract The textural and structural properties of a skeletal Ni catalyst prepared by alkali leaching of aluminum from the rapidly Quenched Ni50Al50 Alloy have been investigated by elemental analysis (ICP-AES), nitrogen physisorption, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and H2 thermal desorption techniques. As compared to Raney Ni, such a skeletal catalyst has a residual Ni2Al3 phase, lower surface area, higher average pore diameter and porosity, larger mean crystallite size, and unit-cell parameter. These differences are attributable to the metastable character of the pristine rapidly Quenched Alloy and their relationship with the catalytic behavior is discussed and correlated.
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skeletal ni catalyst prepared from a rapidly Quenched ni al Alloy and its high selectivity in 2 ethylanthraquinone hydrogenation
Journal of Catalysis, 2001Co-Authors: Bo Liu, Minghua Qiao, Jingfa Deng, Kangnian Fan, Xiaoxin Zhang, Baoning ZongAbstract:Abstract A novel skeletal Ni catalyst, prepared by alkali leaching of a Ni–Al Alloy obtained by the rapid quenching technique, exhibited higher selectivity in hydrogenation of 2-ethylanthraquinone to “active quinones” than that of the Raney Ni catalyst originating from a conventional Alloy. It is suggested that the structural defects of the rapidly Quenched Alloy lead to a high population of the strongly bound hydrogen, which is essential for selective hydrogenation of the carbonyl group.
Xiaoxin Zhang - One of the best experts on this subject based on the ideXlab platform.
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structural and catalytic properties of skeletal ni catalyst prepared from the rapidly Quenched ni50al50 Alloy
Journal of Catalysis, 2004Co-Authors: Minghua Qiao, Kangnian Fan, Baoning Zong, Shuai Wang, Xiaoxin ZhangAbstract:Abstract The textural and structural properties of a skeletal Ni catalyst prepared by alkali leaching of aluminum from the rapidly Quenched Ni50Al50 Alloy have been investigated by elemental analysis (ICP-AES), nitrogen physisorption, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and H2 thermal desorption techniques. As compared to Raney Ni, such a skeletal catalyst has a residual Ni2Al3 phase, lower surface area, higher average pore diameter and porosity, larger mean crystallite size, and unit-cell parameter. These differences are attributable to the metastable character of the pristine rapidly Quenched Alloy and their relationship with the catalytic behavior is discussed and correlated.
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skeletal ni catalyst prepared from a rapidly Quenched ni al Alloy and its high selectivity in 2 ethylanthraquinone hydrogenation
Journal of Catalysis, 2001Co-Authors: Bo Liu, Minghua Qiao, Jingfa Deng, Kangnian Fan, Xiaoxin Zhang, Baoning ZongAbstract:Abstract A novel skeletal Ni catalyst, prepared by alkali leaching of a Ni–Al Alloy obtained by the rapid quenching technique, exhibited higher selectivity in hydrogenation of 2-ethylanthraquinone to “active quinones” than that of the Raney Ni catalyst originating from a conventional Alloy. It is suggested that the structural defects of the rapidly Quenched Alloy lead to a high population of the strongly bound hydrogen, which is essential for selective hydrogenation of the carbonyl group.
Hui-ping Ren - One of the best experts on this subject based on the ideXlab platform.
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Influence of the substituting Ni with Fe on the cycle stabilities of as-cast and as-Quenched La0.7Mg0.3Co0.45Ni2.55 − xFex (x = 0–0.4) electrode Alloys
Materials Characterization, 2010Co-Authors: Yanghuan Zhang, Rafi-ud-din, Hui-ping Ren, Shi-hai Guo, Xin-lin WangAbstract:The electrode Alloys La{sub 0.7}Mg{sub 0.3}Co{sub 0.45}Ni{sub 2.55-x}Fe{sub x} (x = 0, 0.1, 0.2, 0.3, 0.4) are fabricated by casting and rapid quenching techniques. The effects of the substitution of Fe for Ni on the cycle stabilities as well as the structures of the Alloys have been investigated thoroughly. The results indicate that the substitution of Fe for Ni significantly enhances the cycle stability of the Alloys. Furthermore, the positive impact of such substitution on the cycle stability has been observed to be more pronounced for the as-Quenched Alloy as compared to that for the as-cast one. Scanning electron microscopy (SEM) studies demonstrate that all the Alloys exhibit a multiphase structure comprising of two major phases (La, Mg)Ni{sub 3} and LaNi{sub 5} along with a residual phase of LaNi{sub 2}. The substitution of Fe for Ni has been observed to facilitate the formation of a like amorphous structure in the as-Quenched Alloy. With an increase in Fe contents, a significant grain refinement of the as-Quenched Alloy and an obvious enlargement in the lattice constants and the cell volumes of the Alloys have been noticed.
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Investigation on the structures and electrochemical performances of La0.75−xZrxMg0.25Ni3.2Co0.2Al0.1 (x = 0–0.2) electrode Alloys prepared by melt spinning
Journal of Alloys and Compounds, 2009Co-Authors: Yanghuan Zhang, Hui-ping Ren, Shi-hai Guo, Xin-lin WangAbstract:Abstract In order to improve the electrochemical cycle stability of the La–Mg–Ni system A 2 B 7 -type electrode Alloys, La in the Alloy was partially substituted by Zr and the melt-spinning technology was used for preparing La 0.75− x Zr x Mg 0.25 Ni 3.2 Co 0.2 Al 0.1 ( x = 0, 0.05, 0.1, 0.15, 0.2) electrode Alloys. The microstructures and electrochemical performances of the as-cast and Quenched Alloys were investigated in detail. The results obtained by XRD, SEM and TEM showed that the as-cast and Quenched Alloys have a multiphase structure which is composed of two main phases (La, Mg)Ni 3 and LaNi 5 as well as a residual phase LaNi 2 . The substitution of Zr for La leads to an obvious increase of the LaNi 5 phase in the Alloys, and it also helps the formation of a like amorphous structure in the as-Quenched Alloy. The results of the electrochemical measurement indicated that the substitution of Zr for La obviously decreased the discharge capacity of the as-cast and Quenched Alloys, but it significantly improved their cycle stability. The discharge capacity of the Alloys ( x ≤ 0.1) first increased and then decreased with the variety of the quenching rate. The cycle stability of the Alloys monotonously rose with increasing quenching rate.
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Effects of the substitution of Al for Ni on the structure and electrochemical performance of La0.7Mg0.3Ni2.55 − xCo0.45Alx (x = 0–0.4) electrode Alloys
Journal of Materials Science, 2007Co-Authors: Yanghuan Zhang, Hui-ping Ren, Shi-hai Guo, Dongliang Zhao, Xin-lin WangAbstract:In order to improve the cycling stability of La–Mg–Ni system (PuNi3-type) hydrogen storage Alloy, Ni in the Alloy was partially substituted by Al, and La0.7Mg0.3Ni2.55 − xCo0.45Alx (x = 0, 0.1, 0.2, 0.3, 0.4) electrode Alloys were prepared by casting and rapid quenching. The effects of the substitution of Al for Ni on the structure and electrochemical performance of the as-cast and Quenched Alloys were investigated in detail. The results obtained by XRD, SEM and TEM show that the substitution of Al for Ni has an inappreciable influence on the abundance of the LaNi2 phase in the as-Quenched Alloy, while it increases the amount of the LaNi2 phase in the as-cast Alloys. In addition, the substitution of Al for Ni is unfavourable for the formation of an amorphous in the as-Quenched Alloy. The results obtained by the electrochemical measurement indicate that the cycling stabilities of the as-cast and Quenched Alloys are significantly ameliorated with increasing Al content. When Al content increases from 0 to 0.4, the cycle life of the as-cast and Quenched (30 m/s) Alloys enhances from 72 to 132 cycles and from 100 to 136 cycles, respectively.
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Influences of the substitution of Fe for Ni on structures and electrochemical performances of the as-cast and Quenched La0.7Mg0.3Co0.45Ni2.55−xFex (x = 0–0.4) electrode Alloys
Journal of Alloys and Compounds, 2007Co-Authors: Yanghuan Zhang, Hui-ping Ren, Xiao-ping Dong, Xin-lin WangAbstract:Abstract In order to improve the cycle stability of the La–Mg–Ni system PuNi 3 -type hydrogen storage electrode Alloys, Ni in the Alloy was partially substituted by Fe. The La 0.7 Mg 0.3 Co 0.45 Ni 2.55− x Fe x ( x = 0, 0.1, 0.2, 0.3, 0.4) hydrogen storage Alloys were prepared by casting and rapid quenching. The effects of the substitution of Fe for Ni on the structures and electrochemical performances of the as-cast and Quenched Alloys were investigated in detail. The results of the electrochemical measurement indicate that the substitution of Fe for Ni obviously decreases the discharge capacity, high rate discharge capability (HRD) and discharge potential of the as-cast and Quenched Alloys, but it significantly improves their cycle stabilities, and its positive impact on the cycle life of as-Quenched Alloy is much more significant than on that of the as-cast one. The microstructure of the Alloys analyzed by XRD, SEM and TEM show that the as-cast and Quenched Alloys have a multiphase structure which is composed of two major phases (La, Mg)Ni 3 and LaNi 5 as well as a residual phase LaNi 2 . The substitution of Fe for Ni helps the formation of a like amorphous structure in the as-Quenched Alloy. With the increase of Fe content, the grain sizes of the as-Quenched Alloys significantly reduce, and the lattice constants and cell volumes of the Alloys obviously increase.
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Cycle stabilities of the La0.7Mg0.3Ni2.55−xCo0.45Mx (M = Fe, Mn, Al; x = 0, 0.1) electrode Alloys prepared by casting and rapid quenching
Journal of Alloys and Compounds, 2007Co-Authors: Yanghuan Zhang, Hui-ping Ren, Xiao-ping Dong, Ying Cai, Xin-lin WangAbstract:Abstract In order to improve the cycle stability of La–Mg–Ni system (PuNi 3 -type) hydrogen storage Alloy, Ni in the Alloy was partly substituted by Fe, Mn and Al, and the electrode Alloys La 0.7 Mg 0.3 Ni 2.55− x Co 0.45 M x (M = Fe, Mn, Al; x = 0, 0.1) were prepared by casting and rapid quenching. The effects of the substitution of Fe, Mn and Al for Ni and rapid quenching on the microstructures and electrochemical properties of the Alloys were investigated in detail. The results obtained by XRD, SEM and TEM indicate that element substitution has no influence on the phase compositions of the Alloys, but it changes the phase abundances of the Alloys. Particularly, the substitution of Al and Mn obviously raises the amount of the LaNi 2 phase. The substitution of Al and Fe leads to a significant refinement of the as-Quenched Alloy's grains. The substitution of Al strongly restrains the formation of an amorphous in the as-Quenched Alloy, but the substitution of Fe is quite helpful for the formation of an amorphous phase. The effects of the substitution of Fe, Mn and Al on the cycle stabilities of the as-cast and Quenched Alloys are different. The positive influence of the substitution elements on the cycle stabilities of the as-cast Alloys is in proper order Al > Fe > Mn, and for as-Quenched Alloys, the order is Fe > Al > Mn. Rapid quenching engenders an inappreciable influence on the phase composition, but it markedly enhances the cycle stabilities of the Alloys.
