1. Department of Materials Science and Engineer, Lanzhou University of Technology, Lanzhou 730050, Gansu, China 2. State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals, Lanzhou 730050, Gansu, Chinaa
Abstract：The La- Y- Ni A2B7- type La0. 1NdxY0. 9-xNi3. 25Mn0. 15Al0. 1 (x=0, 0. 1, 0. 2, 0. 3, 0. 4, 0. 5, 0. 6) hydrogen storage alloys were investigated for the study of effect of rare earth elements Nd on microstructure and electrochemical properties of the Alloys. The phase structure analysis of the alloy showed that the main microstructure of the alloy is Ce2Ni7- type phase. When x=0. 4, the phase abundance of the alloy Ce2Ni7- type can reach 98. 32%. The cell volume of the Ce2Ni7- type phase gradually decreases with the decrease of the average atomic radius of the A terminal element in the annealed alloys. Electrochemical analysis showed that the cycle life of the alloy electrode is greatly improved when the rare earth element Nd is added, and the x=0. 4 alloy electrode has the highest electrochemical discharge capacity (377. 7mA·h/g); The x=0. 5 alloy electrode has the best cycle life (S100=88. 17%). the main factor controlling the dynamic performance of the alloy electrode is the diffusion of hydrogen in the alloy. When x=0. 4, the high rate discharge performance of the alloy electrode is the best (HRD900=82. 88%). When x=0, 0. 1, the main factor controlling the dynamic performance of the alloy electrode is the diffusion of hydrogen in the alloy at this time; when 0. 2≤x≤0. 6, it is controlled the dynamic characteristics of the alloy electrode by the charge transfer rate on the surface of the alloy and the diffusion of hydrogen in the alloy phase at this time.
[1] Kadir K, Sakai T, Uehara I. Synthesis and structure determination of a new series of hydrogen storage alloys;RMg2Ni9(R=La, Ce, Pr, Nd, Sm and Gd) built from MgNi2Laves-type layersAlternating with AB5layers[J]. Journal of Alloys and Compounds,1997, 257(257): 115.[2] Kohno T, Yoshida H, Kawashima F, et al. Hydrogen storageProperties of new ternary system alloys:La2MgNi9,La5Mg2Ni23,La3MgNi14[J]. Journal of Alloys and Compounds, 2000, 311(2): L5.[3] Liu Y, Pan H, Gao M, et al. Degradation mechanism of the La-Mg-Ni-based metal hydride electrode La0.7Mg0.3Ni3.4Mn0.1[J].Journal of the Electrochemical Society, 2005, 152(6): A1089.[4] 董小平, 杨丽颖, 庞艳荣, 等. 放电等离子烧结制备储氢合金的应用研究现状[J]. 粉末冶金工业, 2014, 24(5): 44.[5] 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]. Materials Chemistry & Physics, 2017, 200: 164-178.[6] V. V. Berezovets’, R. V. Denys, O. B. Ryabov, et al. Hydrides of substituted derivatives based on the YNi3compound[J]. Materials Science, 2007, 43(4): 499-507[7] Xiong W, Yan H, 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.[8] 赵磊,罗永春,邓安强,等.无镁超点阵结构A2B7型La1-xYx(Ni, Mn, Al)3.5合金储氢和电化学性能研究[J].高等学校化学学报, 2018年4月(已接受).[9] Pan H G, Liu Y F, Gao M X, et al. Electrochemical studies on La0.7Mg0.3Ni3.4-xCo0.6Mnx metal hydride electrodes alloys[J]. Materials Chemistry and Physics, 2004, 84(1): 171-181.[10] Liu Y F, Pan H G, Gao M X. The effect of Mn substitution for Ni on the structural and electrochemicalproperties of La0.7Mg0.3Ni2.55-xCo0.45Mnx hydrogen storage electrodes alloys[J]. International Journal of Hydrogen Energy, 2004, 29: 297-305.[11] Pan H, Jin Q, Gao M, et al. Effect of the cerium content on the structural and electrochemical properties of the La0.7?xCexMg0.3Ni2.875Mn0.1Co0.525, (x=0-0.5) hydrogen storage alloys[J]. Journal of Alloys & Compounds, 2004, 373(1-2): 237-245.[12] 林振, 罗永春, 高志杰,等. 钆对La-Mg-Ni系A2B7型储氢合金微观结构和电化学性能的影响[J]. 中国稀土学报, 2011, 29(3): 344-350.[13] Yasuoka S, Magari Y, Murata T, et al. Development of high-capacity nickel-metal hydride batteries using superlattice hydrogen-absorbing alloys[J]. Journal of Power Sources, 2006, 156(2): 662-666.[14] Li Y, Han D, Han S, et al. Effect of rare earth elements on electrochemical properties of La-Mg-Ni-based hydrogen storage alloys[J]. International Journal of Hydrogen Energy, 2009, 34(3): 1399-1404.[15] 王浩. La-Y-Ni系超点阵结构A2B7型储氢合金微观组织和电化学性能研究[D]. 兰州理工大学, 2017.[16] R.A.Young. The Rietveld Method.London, Oxford University Press, 1995: 1-75.[17] Yartys V, Noreus D, Latroche M. Metal hydrides as negative electrode materials for Ni-MH batteries[J]. Applied Physics A, 2016, 122(1): 1-11.[18] Liu J J, Li Y, Han D, et al. Electrochemical performance and capacity degradation mechanism of single-phaseLa-Mg-Ni-based hydrogen storage alloys[J]. Journal of Power Sources, 2015, 300: 77-86.[19] Enomoto M, Ohata Y, Uchida H. Reaction kinetics of H2, O2, and H2O with rare earths (Y, La, Ce, Pr, Nd, Gd, Tb, Dy, and Er) at 298K[J]. Journal of Alloys & Compounds, 2013, 580(Suppl1): S3-S5.[20] 周增林, 宋月清, 崔舜, 等. Nd替代La对La-Mg-Ni系A2B7型贮氢电极合金性能的影响[J]. 中国有色金属学报, 2007, 17(1): 45-52.[21] Notten P H L, Hokkeling P. Double‐Phase Hydride Forming Compounds: A New Class of Highly Electrocatalytic Materials[J]. Journal of the Electrochemical Society, 1991, 138(7) :1877-1885.[22] Zhang G, Popov B N, White R E. Electrochemical determination of the diffusion coefficient of hydrogen through an LaNi4.25Al0.75 electrode in alkaline aqueous solution[J]. Journal of the Electrochemical Society, 1995, 142(8): 2695?2698.
2019, Vol. 26 
