Abstract：La0.7Y0.3Ni3.4-xMnxAl0.1(x=0~0.5) alloys were prepared by vacuum arc melting method and the casted ingots were annealed under 900 degrees in argon. The Effect of Mn element replacing Ni on the microstructure, hydrogen storage behavior and electrochemical properties were systematically investigated via XRD, SEM, EDS and electrochemical test methods. The results showed that the main phase of the annealed alloy was Ce2Ni7-type and the inpurity phase was PuNi3-type, CeNi3-type and Ce5Co19-type. Abundance of the main phase increased first and then decreased with the increase of Mn content and when x = 0.2, its maximum abundance was reached at 89.03%. The tendency of hydrogen-induced amorphization of the alloy was effectively alleviated by the increase of the Mn content. With the increase of Mn content, the discharge capacity of the alloy electrode increased gradually, while the stability of charge-discharge cycle decreased gradually. The maximum discharge capacity and optimal cycle stability of the alloy electrode were 308.6 mAh/g and 95.09% respectively. The kinetic analysis indicated that High rate discharge ability of the electrode was controlled by the diffusion of hydrogen atoms in the alloy phase.
[1]Kohno T, Yoshida H, KawashimaA F, et al.Hydrogen storage properties of new ternary system alloys: La2MgNi9,La5Mg2Ni23,La3MgNi14[J].Journal of Alloys & Compounds, 2000, 311(2):5-7[2]王浩, 罗永春, 邓安强, 等.系型储氢合金表面包覆及其电化学性能研究[J].金属功能材料, 2018, 25(1):23-29[3]李倩, 刘永活, 高峰，等.真空感应熔炼制备--型储氢合金工艺研究[J].金属功能材料, 2014, 21(3):34-36[4] Liu J, Li Y, Han D, et al.Electrochemical performance and capacity degradation mechanism of single-phase La-Mg-Ni-based hydrogen storage alloys[J]. [J].Journal of Power Sources, 2015, 300:77-86[5]Liu Y, Pan H, Gao M, et al.Degradation mechanism of the La-Mg-Ni-based hydride electrode La07Mg0.3Ni3.4Mn0.1[J].Journal of the Electrochemical Society, 2005, 152(6):A1089-A1095[6] Charbonnier V, Zhang J, Monnier J, et al.Relationship between H2, sorption properties and aqueous corrosion mechanisms in A2Ni7, hydride forming alloys (A =Y, Gd or Sm)[J].[J].Journal of Power Sources, 2016, 326:146-155[7]Charbonnier V, Zhang J, Monnier J, et al.Structural and Hydrogen Storage Properties of Y2Ni7 Deuterides Studied by Neutron Powder Diffraction[J].Journal of Physical Chemistry C, 2015, 119(22):12218-12225[8]Baddour-hadjean R, Meyer L, Pereira-Ramos J P, et al.An electrochemical study of new La1?xCexY2Ni9 (0≤x≤1) hydrogen storage alloys[J].Electrochimica Acta, 2001, 46(15):2385-2393[9]Yan H Z, Xiong W, Wang L, et al.Investigations on AB3,A2B7 and A5B19-type La-Y-Ni system hydrogen storage alloys[J].International Journal of Hydrogen Energy, 2017, 42(4):2257-2264[10] 赵磊, 镧-钇（Y）-镍系A2B7型合金储氢性能及稀土钇的影响[D].兰州理工大学, 2018.[11] Ouyang L, Huang J, Wang H, et al.Progress of hydrogen storage alloys for Ni-MH rechargeable power batteries in electric vehicles: A review[J]. [J].Materials Chemistry & Physics, 2017, 200:164-178[12]Liu J, Han S, Li Y, et al.An investigation on phase transformation and electrochemical properties of as-cast and annealed La075Mg0.25Nix (x=3.0,3.3,3.5,3.8) alloys[J].Journal of Alloys & Compounds, 2013, 552(3):119-126[13]Xiong W, Yan H Z, Wang L, et al.Characteristics of A2B7-type La-Y-Ni-based hydrogen storage alloys modified by partially substituting Ni with Mn[J].International Journal of Hydrogen Energy, 2017, 42(15):10131-10141[14]Wang W, Chen Y G, Tao M D, et al.Hydrogen-induced amorphization in LaNi3-xMnx compounds[J].Journal of Rare Earths, 2010, 28(3):443-446[15] Young R A, The Rietveld Method[M].London, Oxford University Press, 1995: 1-75.[16]贾志华, 王玉平.储氢合金吸氢量测试方法[J].金属功能材料, 2004, 11(5):28-31[17]Zheng G, Popov B N, White R E, Electrochemical determination of the diffusion coefficient of hydrogen through an LaNi.Al025 electrode in alkaline aqueous solution[J].Journal of The Electrochemical Society, 1995, 142(8):2695-2698[18] Notten P H L, Hokkel P, .Double phase hydride forming compounds: a new class of highly electrocatalytic materials[J][J].Journal of The Electrochemical Society, 1991, 138(7):1877-1885[19]K.Yong,TOuchi,H Shen,Hydrogen induced amorphization of LaMgNi4 phase in metal hydride alloys[J].International Journal of Hydrogen Energy, 2015, 40(29):8941-8947[20]董小平, 杨丽颖, 朱凯宁，等.储氢合金电极失效的机理分析及研究进展[J].稀有金属与硬质合金, 2011, 39(04):25-30[21]Liu J J, Han S M, Han D, et al.Electrochemical performance and capacity degradation mechanism of single –phase La-Mg-Ni-based hydrogen storage alloys[J].Journal of Power source, 2015, 300(30):77-86[22] Reilly J J.Metal hydride electrode[M]. In: J. O. Besenhard (Ed.), handbook of battery materials. Wiley, New York, 2000.
2020, Vol. 27 