To ameliorate the electrochemical hydrogen storage properties of RE-Mg-Ni-Mn-based AB2-type electrode alloys,La element was partially substituted by Ce,and La1-xCexMgNi3.5Mn0.5(x=0,0.1,0.2,0.3,0.4)alloys were fabricat...To ameliorate the electrochemical hydrogen storage properties of RE-Mg-Ni-Mn-based AB2-type electrode alloys,La element was partially substituted by Ce,and La1-xCexMgNi3.5Mn0.5(x=0,0.1,0.2,0.3,0.4)alloys were fabricated by casting and melt spinning.The effects of Ce content on structures and electrochemical hydrogen storage properties of prepared alloys were studied in detail.Results show that the experimental alloys consist of LaMgNi4 and LaNi5 phases.The variation of Ce content,instead of changing phase composition,results in an obvious phase abundance change in the alloys,namely the amount of LaMgNi4 and LaNi5 phases,respectively,increases and decreases with Ce content growing.Moreover,the partial substitution of Ce for La leads to that the lattice keeps constant,cell volumes clearly decreases and the alloy grains are markedly refined.The electrochemical measurements reveal that the as-cast and as-spun alloys obtain the maximum discharge capacities at the first cycling without any activation needed.With Ce content increasing,the discharge capacity of as-cast alloys visibly decreases.By contrast,the as-spun alloys have the maximum discharge capacity value.The substitution of Ce for La dramatically promotes the cycle stability.Moreover,the electrochemical kinetic performances of as-cast and asspun alloys first increase and then decrease with Ce content increasing.展开更多
Preparation of La-Mg-Ni-Co-Al-based AB2-type alloys La0.8-xCe0.2YxMgNi3.4Co0.4Al0.1(x=0,0.05,0.10,0.15,0.20)was performed using melt spinning technology.The influences of spun rate and Y content on structures and elec...Preparation of La-Mg-Ni-Co-Al-based AB2-type alloys La0.8-xCe0.2YxMgNi3.4Co0.4Al0.1(x=0,0.05,0.10,0.15,0.20)was performed using melt spinning technology.The influences of spun rate and Y content on structures and electrochemical hydrogen storage characteristics were studied.The base phase LaMgNi4 and the lesser phase LaNis were detected by X-ray diffraction(XRD)and scanning electron microscope(SEM).The variations of spinning rate and Y content cause an obvious change in phase content,but without altering phase composition,namely,with spinning rate and Y content growing,LaMgNi4 phase content augments while LaNi5 content declines.Furthermore,melt spinning and the replacing La by Y refine the grains dramatically.The electrochemical tests show a favorable activation capability of the two kinds of alloys,and the maximum discharge capacities are achieved during the first cycle.Discharge capacity firstly increases and subsequently decreases with spinning rate rising,while cycle stability is ameliorated and discharge capacity decreases with Y addition increasing.It is found that the amelioration of cycle stability is due to the enhancement of anti-pulverization,anti-corrosion and antioxidation abilities by both replacement of La with Y and melt spinning.Moreover,with the increase of Y addition and/or spinning rate,the electrochemical kinetics that contain charge transfer rate,limiting current density(IL),hydrogen diffusion coefficient(D)and the high rate discharge ability(HRD)firstly augment and then reduce.展开更多
La-Mg-Ni-Mn-based AB2-type La（1–x）CexMgNi（3.5）Mn（0.5）（x=0–0.4） alloys were prepared by melt spinning technology. The detections of X-ray diffraction（XRD） and scanning electron microscopy（SEM） indicated t...La-Mg-Ni-Mn-based AB2-type La（1–x）CexMgNi（3.5）Mn（0.5）（x=0–0.4） alloys were prepared by melt spinning technology. The detections of X-ray diffraction（XRD） and scanning electron microscopy（SEM） indicated that the experimental alloys consisted of a major phase LaMgNi4 and a secondary phase LaNi5. With spinning rate growing, the abundance of LaMgNi4 phase increased and that of LaNi5 phase decreased. Moreover, with the melt spinning rate increasing, both the lattice constants and cell volumes increased, and further accelerated the grains refinement of the alloys. The electrochemical tests showed that the as-spun alloys possessed excellent capability of activation, achieving the maximum discharge capacities just at the first cycling without any activation needed. As for the as-spun alloys, its discharge potential characteristics could be improved obviously by adopting the technology of melt spinning. In addition, the melt spinning raised electrochemical cycle stability of the alloys, the main reason was that the melt spinning enhanced the anti-pulverization ability of the alloys. With spinning rate increasing, the discharge capacity of the alloys presented a tendency to increase firstly then decrease. Moreover, the electrochemical kinetics of the alloys showed the same trend under fixed condition.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51161015,51371094 and 51471054)the Natural Science Foundation of Inner Mongolia,China(No.2015MS0558)
文摘To ameliorate the electrochemical hydrogen storage properties of RE-Mg-Ni-Mn-based AB2-type electrode alloys,La element was partially substituted by Ce,and La1-xCexMgNi3.5Mn0.5(x=0,0.1,0.2,0.3,0.4)alloys were fabricated by casting and melt spinning.The effects of Ce content on structures and electrochemical hydrogen storage properties of prepared alloys were studied in detail.Results show that the experimental alloys consist of LaMgNi4 and LaNi5 phases.The variation of Ce content,instead of changing phase composition,results in an obvious phase abundance change in the alloys,namely the amount of LaMgNi4 and LaNi5 phases,respectively,increases and decreases with Ce content growing.Moreover,the partial substitution of Ce for La leads to that the lattice keeps constant,cell volumes clearly decreases and the alloy grains are markedly refined.The electrochemical measurements reveal that the as-cast and as-spun alloys obtain the maximum discharge capacities at the first cycling without any activation needed.With Ce content increasing,the discharge capacity of as-cast alloys visibly decreases.By contrast,the as-spun alloys have the maximum discharge capacity value.The substitution of Ce for La dramatically promotes the cycle stability.Moreover,the electrochemical kinetic performances of as-cast and asspun alloys first increase and then decrease with Ce content increasing.
基金financially supported by the National Natural Science Foundations of China(Nos.51761032,51871125 and 51471054).
文摘Preparation of La-Mg-Ni-Co-Al-based AB2-type alloys La0.8-xCe0.2YxMgNi3.4Co0.4Al0.1(x=0,0.05,0.10,0.15,0.20)was performed using melt spinning technology.The influences of spun rate and Y content on structures and electrochemical hydrogen storage characteristics were studied.The base phase LaMgNi4 and the lesser phase LaNis were detected by X-ray diffraction(XRD)and scanning electron microscope(SEM).The variations of spinning rate and Y content cause an obvious change in phase content,but without altering phase composition,namely,with spinning rate and Y content growing,LaMgNi4 phase content augments while LaNi5 content declines.Furthermore,melt spinning and the replacing La by Y refine the grains dramatically.The electrochemical tests show a favorable activation capability of the two kinds of alloys,and the maximum discharge capacities are achieved during the first cycle.Discharge capacity firstly increases and subsequently decreases with spinning rate rising,while cycle stability is ameliorated and discharge capacity decreases with Y addition increasing.It is found that the amelioration of cycle stability is due to the enhancement of anti-pulverization,anti-corrosion and antioxidation abilities by both replacement of La with Y and melt spinning.Moreover,with the increase of Y addition and/or spinning rate,the electrochemical kinetics that contain charge transfer rate,limiting current density(IL),hydrogen diffusion coefficient(D)and the high rate discharge ability(HRD)firstly augment and then reduce.
基金Project supported by National Natural Science Foundation of China(51161015,51371094,51471054)
文摘La-Mg-Ni-Mn-based AB2-type La（1–x）CexMgNi（3.5）Mn（0.5）（x=0–0.4） alloys were prepared by melt spinning technology. The detections of X-ray diffraction（XRD） and scanning electron microscopy（SEM） indicated that the experimental alloys consisted of a major phase LaMgNi4 and a secondary phase LaNi5. With spinning rate growing, the abundance of LaMgNi4 phase increased and that of LaNi5 phase decreased. Moreover, with the melt spinning rate increasing, both the lattice constants and cell volumes increased, and further accelerated the grains refinement of the alloys. The electrochemical tests showed that the as-spun alloys possessed excellent capability of activation, achieving the maximum discharge capacities just at the first cycling without any activation needed. As for the as-spun alloys, its discharge potential characteristics could be improved obviously by adopting the technology of melt spinning. In addition, the melt spinning raised electrochemical cycle stability of the alloys, the main reason was that the melt spinning enhanced the anti-pulverization ability of the alloys. With spinning rate increasing, the discharge capacity of the alloys presented a tendency to increase firstly then decrease. Moreover, the electrochemical kinetics of the alloys showed the same trend under fixed condition.
