Structural and electrochemical properties of high-capacity Ml-Mg-Ni-based hydrogen storage alloys

Abstract

The Ml-Mg-Ni-based (Ml= La-rich mixed lanthanide) hydrogen storage alloy Ml_0.88Mg_0.12Ni_3.0Mn_0.10Co_0.55Al_0.10 was prepared by inductive melting. The micro-structure was analyzed by XRD and SEM. The alloy consists mainly of CaCu₅-type phase, Ce₂Ni₇-type phase and Pr₅Co₁₉-type phase. The electrochemical measurements show that the maximum discharge capacity is 386 mAh/g, 16.3% higher than that of the commercial AB₅-type alloy (332 mAh/g). At discharge current density of 1 100 mA/g, high rate dischargeability is 62%, while that of the AB₅-type alloy is only 45%. The discharge capacity decreases to 315 mAh/g after 300 charge/ discharge cycles, 81.5% of the maximum discharge capacity.

Keywords

Ni/MH batteries / hydrogen storage alloys / Ml-Mg-Ni-based alloys / electrochemical properties

References

[1] Pan H G, Ma J X, Wang C S, Chen S A, Wang X H, Chen C P, Wang Q D. Studies on the electrochemical properties of MlNi_4.32-xCo_xAl_0.7 hydride alloy electrodes. Journal of Alloys and Compounds, 1999, 293-295: 648–652

[2] Kadir K, Sakai T, Uehara I. Structural investigation and hydrogen capacity of LaMg₂Ni₉ and (Y_0.65Ca_0.35)(Mg_1.32Ca_0.68)Ni₉ of the AB₂C₉ type structure. Journal of Alloys and Compounds, 2000, 302(1-2): 112–117

[3] Chen J, Takeshita H T, Tanaka H, Kuriyama N, Sakai T, Uehara I, Haruta M. Hydriding properties of LaNi₃ and CaNi₃ and their substitutes with PuNi₃-structure. Journal of Alloys and Compounds, 2000, 302(1-2): 304–313

[4] Kohno T, Yoshida H, Kawashima F, Inaba T, Sakai I, Yamamoto M, Kanda M. Hydrogen storage properties of new ternary system alloys: La₂MgNi₉, La₅Mg₂Ni₂₃, La₃MgNi₁₄. Journal of Alloys and Compounds, 2000, 311(2): L5–L7

[5] Akiba E, Hayakawa H, Kohno T. Crystal structure of novel La-Mg-Ni hydrogen absorbing alloys. Journal of Alloys and Compounds, 2006, 408-412: 280–283

[6] Pan H G, Liu Y F, Gao M X, Zhu Y F, Lei Y Q. The structural and electrochemical properties of La_0.7Mg_0.3(Ni_0.85Co_0.15)_x (x= 3.0-5.0) hydrogen storage alloys. International Journal of Hydrogen Energy, 2003, 28(11): 1219–1228

[7] Liu Y F, Pan H G, Gao M X, Li R, Lei Y Q. Influences of Ni addition on the structures and electrochemical properties of La_0.7Mg_0.3Ni_2.65+xCo_0.75Mn_0.1 (x= 0.0-0.5) hydrogen storage alloys. Journal of Alloys and Compounds, 2005, 389(1-2): 281–289

[8] Liao B, Lei Y Q, Chen L X, Lu G L, Pan H G, Wang Q D. Effect of Co substitution for Ni on the structural and electrochemical properties of La₂Mg(Ni_1-xCo_x)9 (x= 0.1–0.5) hydrogen storage electrode alloys. Electrochimica Acta, 2004, 50(4): 1057–1063

[9] Liu Y F, Pan H G, Zhu Y F, Li R, Lei Y Q. Influence of Mn content on the structural and electrochemical properties of the La_0.7Mg_0.3Ni_4.25-xCo_0.75Mnx hydrogen storage alloys. Materials Science and Engineering A, 2004, 372(1-2): 163–172

[10] Liao B, Lei Y Q, Chen L X, Lu G L, Pan H G, Wang Q D. The effect of Al substitution for Ni on the structure and electrochemical properties of AB₃-type La₂Mg(Ni_1-xAlx)₉ (x= 0–0.05) alloys. Journal of Alloys and Compounds, 2005, 404-406: 665–668

[11] Li M, Han S M, Li Y, Guan W, Mao L R, Hu L. Study on the phase structure and electrochemical properties of RE_0.93Mg_0.07Ni_2.96Co_0.60Mn_0.37Al_0.17 hydrogen storage alloy. Electrochimica Acta, 2006, 51(26): 5926–5931

[12] Zhang Z, Han S M, Li Y, Jing T F. Electrochemical properties of Ml_1–xMg_xNi_3.0Mn_0.10Co_0.55Al_0.10 (x= 0.05–0.30) hydrogen storage alloys. Journal of Alloys and Compounds, 2007, 431(1–2): 208–211

[13] Zhang Y H, Dong X P, Wang G Q, Ren J Y, Guo S H, Wang X L. Microstructures and Electrochemical Performances of La₂Mg(Ni_0.85Co_0.15)₉Cr_x (x= 0-0.2) Electrode Alloys Prepared by Casting and Rapid Quenching. Rare metal Materials and Engineering, 2006, 35(6): 876–879 (in Chinese)

[14] Iwakura C, Oura T, Inoue H, Matsuoka M. Effects of substitution with foreign metals on the crystallographic, thermodynamic and electrochemical properties of AB₅-type hydrogen storage alloys. Electrochimica Acta, 1996, 41(1): 117–121

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