| 摘要 |
An intermetallic alloy, having a CaCu5-type hexagonal crystallographic structure (space group P6/mmm) and the composition M'M5 (M' = one or more rare earth elements; M = one or more of transition metals, Al, B, Ge, Si, Mg and Ca), has the following novel characteristics: a particle diameter of 0.1-400 mu m, a lattice volume of 86.68-97 ?A<3> and a crystallite size of less than 0.1 mu m. Preferably, M' = La, optionally together with one or more of Ce, Pr and Nd, and M = Ni together with one or more of Cu, Co, Mn and Al. Also claimed are processes for (i) preparation of the above alloy by grinding a mixture of powders or chips containing the elements M and M', in the absence of solvent and external heating, in a ball mill capable of operating in the energy range 10<-3>-10 J per impact; and (ii) hydriding of the above alloy in an electrochemical cell, having an electrode with the alloy as active material, a Pt wire or Ni(OH)2 as counter-electrode, a highly basic aqueous electrolyte a nd optionally a reference electrode, by current passage to effect insertion of 6 H<+> ions per unit formula M'M5 of the electrode active material. Further claimed are (1) a metal hydride, preferably M'M5Hx (x = 0 to 6), obtained by the above hydriding process; (2) an electrode having the above hydride M'M5Hx as active material; and (3) a rechargeable battery having the above electrode as the negative electrode. |
