Abstract: Provided is a hydrogen storage alloy which is characterized in that two or more crystal phases having different crystal structures are layered in a c-axis direction of the crystal structures. The hydrogen storage alloy is further characterized in that a difference between a maximum value and a minimum value of a lattice constant a in the crystal structures of the laminated two or more crystal phases is 0.03 ? or less.

Abstract: It is an object of the present invention to improve the cycle performance in a nickel-metal hydride battery using a rare earth-Mg—Ni type alloy. The present invention provides a nickel-metal hydride battery having a negative electrode including an La—Mg—Ni based hydrogen absorbing alloy, wherein the hydrogen absorbing alloy has a crystal phase having Gd2Co7 type crystal structure and contains calcium.

Abstract: Provided is a hydrogen storage alloy which is characterized in that two or more crystal phases having different crystal structures are layered in a c-axis direction of the crystal structures. The hydrogen storage alloy is further characterized in that a difference between a maximum value and a minimum value of a lattice constant a in the crystal structures of the laminated two or more crystal phases is 0.03 ? or less.

Abstract: Provided is a hydrogen storage alloy which is characterized in that two or more crystal phases having different crystal structures are layered in a c-axis direction of the crystal structures. The hydrogen storage alloy is further characterized in that a difference between a maximum value and a minimum value of a lattice constant a in the crystal structures of the laminated two or more crystal phases is 0.03 ? or less.

Abstract: Provided is a hydrogen storage alloy which is characterized in that two or more crystal phases having different crystal structures are layered in a c-axis direction of the crystal structures. The hydrogen storage alloy is further characterized in that a difference between a maximum value and a minimum value of a lattice constant a in the crystal structures of the laminated two or more crystal phases is 0.03 ? or less.

Abstract: The present invention provides a hydrogen absorbing alloy containing a phase of a Gd2Co7 type crystal structure, wherein the phase exists at a ratio of 10 weight % or higher in the entire hydrogen absorbing alloy and yttrium is contained at a ratio of 2 mol % or more and 10 mol % or less in the entire hydrogen absorbing alloy.

Abstract: Provided is a hydrogen storage alloy which is characterized in that two or more crystal phases having different crystal structures are layered in a c-axis direction of the crystal structures. The hydrogen storage alloy is further characterized in that a difference between a maximum value and a minimum value of a lattice constant a in the crystal structures of the laminated two or more crystal phases is 0.03 ? or less.

Abstract: Provided is a hydrogen storage alloy which is characterized in that two or more crystal phases having different crystal structures are layered in a c-axis direction of the crystal structures. The hydrogen storage alloy is further characterized in that a difference between a maximum value and a minimum value of a lattice constant a in the crystal structures of the laminated two or more crystal phases is 0.03 ? or less.

Abstract: The present invention provides a hydrogen absorbing alloy containing a phase of a Pr5Co19 type crystal structure having a composition defined by a general formula A(4?w)B(1+w)C19 (A denotes one or more element(s) selected from rare earth elements including Y (yttrium); B denotes an Mg element; C denotes one or more element(s) selected from a group consisting of Ni, Co, Mn, and Al; and w denotes a numeral in a range from ?0.1 to 0.8) and having a composition as a whole defined by a general formula R1xR2yR3z (15.8?x?17.8, 3.4?y?5.0, 78.8?z?79.6, and x+y+z=100; R1 denotes one or more element(s) selected from rare earth elements including Y (yttrium); R2 denotes an Mg element, R3 denotes one or more element(s) selected from a group consisting of Ni, Co, Mn, and Al; the numeral of Mn+Al in the z is 0.5 or higher; and the numeral of Al in the z is 4.1 or lower).

Abstract: A nickel electrode for an alkaline secondary battery includes an electrically conductive base plate, and an active material particle supported on the conductive base plate and including a complex particle with a surface layer that mainly formed of a high-order cobalt compound whose oxidation number of cobalt is higher than +2 on a surface of a core layer particle that forms a high-order nickel hydroxide whose oxidation number of nickel is higher than +2. Lithium (Li) is contained to be a solid solution in the active material particle from 0.01 to 0.5 wt % of a converted amount as a lithium metal by weight of lithium metal divided by a total weight of the high-order nickel hydroxide, the high-order cobalt compound and the lithium metal.

Abstract: The present invention aims to increase the discharge capacity and to improve the cycle life performance in a nickel-metal hydride rechargeable battery using a La—Mg—Ni based hydrogen-absorbing alloy as an active material of a negative electrode. The present invention provides a hydrogen-absorbing alloy represented by the general formula (1): M1uMgvCawM2xNiyM3z . . . (1) (wherein, M1 is one or more elements selected from rare earth elements; M2 is one or more elements selected from the group consisting of Group 3A elements; Group 4A elements, Group 5A elements, and Pd (excluding rare earth elements); M3 is one or more elements selected from the group consisting of Group 6A elements, Group 7A elements, Group 8 elements, Group 1B elements, Group 2B elements, and Group 3B elements (excluding Ni and Pd); u, v, w, x, y, and z are numbers satisfying, u+v+w+x+y+z=100, 3.4?v?5.9, 0.8?w?3.1, 0?(x+z)?5, and 3.2?(y+z)/(u+v+w+x)?3.

Abstract: A hydrogen storage alloy containing a phase of a chemical composition defined by a general formula A5·xB1+xC24: wherein in the general formula A5·xB1+xC24, A denotes one or more element(s) selected from rare earth elements; B denotes one or more element(s) selected from a group consisting of Mg, Ca, Sr, and Ba; C denotes one or more element(s) selected from a group consisting of Ni, Co, Mn, Al, Cr, Fe, Cu, Zn, Si, Sn, V, Nb, Ta, Ti, Zr, and Hf; and x denotes a numeral in a range from ?0.1 to 0.8: and the phase has a crystal structure belonging to a space group of R-3m and having a length ratio of the c-axis to the a-axis of the lattice constant in a range of 11.5 to 12.5.

Abstract: The present invention provides a hydrogen absorbing alloy containing a phase of a Pr5Co19 type crystal structure having a composition defined by a general formula A(4-w)B(1+w)C19 (A denotes one or more element(s) selected from rare earth elements including Y (yttrium); B denotes an Mg element; C denotes one or more element(s) selected from a group consisting of Ni, Co, Mn, and Al; and w denotes a numeral in a range from ?0.1 to 0.8) and having a composition as a whole defined by a general formula R1xR2yR3z (15.8?x?17.8, 3.4?y?5.0, 78.8?z?79.6, and x+y+z=100; R1 denotes one or more element(s) selected from rare earth elements including Y (yttrium); R2 denotes an Mg element, R3 denotes one or more element(s) selected from a group consisting of Ni, Co, Mn, and Al; the numeral of Mn+Al in the z is 0.5 or higher; and the numeral of Al in the z is 4.1 or lower).

Abstract: The present invention provides a hydrogen absorbing alloy containing a phase of a Pr5Co19 type crystal structure having a composition defined by a general formula A(4?w)B(1+w)C19 (A denotes one or more element(s) selected from rare earth elements including Y (yttrium); B denotes an Mg element; C denotes one or more element(s) selected from a group consisting of Ni, Co, Mn, and Al; and w denotes a numeral in a range from ?0.1 to 0.8) and having a composition as a whole defined by a general formula R1xR2yR3z (15.8?x?17.8, 3.4?y?5.0, 78.8?z?79.6, and x+y+z=100; R1 denotes one or more element(s) selected from rare earth elements including Y (yttrium); R2 denotes an Mg element, R3 denotes one or more element(s) selected from a group consisting of Ni, Co, Mn, and Al; the numeral of Mn+Al in the z is 0.5 or higher; and the numeral of Al in the z is 4.1 or lower).

Abstract: It is an object of the present invention to improve the cycle performance in a nickel-metal hydride battery using a rare earth-Mg—Ni type alloy. The present invention provides a nickel-metal hydride battery having a negative electrode including an La—Mg—Ni based hydrogen absorbing alloy, wherein the hydrogen absorbing alloy has a crystal phase having Gd2Co7 type crystal structure and contains calcium.

Abstract: Provided is a hydrogen storage alloy which is characterized in that two or more crystal phases having different crystal structures are layered in a c-axis direction of the crystal structures. The hydrogen storage alloy is further characterized in that a difference between a maximum value and a minimum value of a lattice constant a in the crystal structures of the laminated two or more crystal phases is 0.03 ? or less.

Abstract: For accomplishing the subjects, the invention provides a nickel electrode material for use in a nickel electrode, wherein the positive-electrode material constituting the electrode material comprises: positive active material particles which comprise as the main component either a nickel hydroxide or a solid solution in a nickel hydroxide of one or more other elements and in which part of the nickel hydroxide has been oxidized; and a coating layer formed on the surface of the positive active material particles and comprising as the main component a high-order cobalt compound in which the cobalt has an oxidation number larger than 2, the average oxidation number of the nickel in the positive active material particles and the cobalt in the coating layer being from 2.04 to 2.40, and the positive-electrode material having a tap density of 2.0 g/cm3 or higher.

Abstract: The present invention provides a hydrogen absorbing alloy containing a phase of a Pr5Co19 type crystal structure having a composition defined by a general formula A(4?w)B(1+w)C19 (A denotes one or more element(s) selected from rare earth elements including Y (yttrium); B denotes an Mg element; C denotes one or more element(s) selected from a group consisting of Ni, Co, Mn, and Al; and w denotes a numeral in a range from ?0.1 to 0.8) and having a composition as a whole defined by a general formula R1xR2yR3z (15.8?x?17.8, 3.4?y?5.0, 78.8?z?79.6, and x+y+z=100; R1 denotes one or more element(s) selected from rare earth elements including Y (yttrium); R2 denotes an Mg element, R3 denotes one or more element(s) selected from a group consisting of Ni, Co, Mn, and Al; the numeral of Mn+Al in the z is 0.5 or higher; and the numeral of Al in the z is 4.1 or lower).

Abstract: The present invention provides a hydrogen absorbing alloy containing a phase of a Gd2CO7 type crystal structure, wherein the phase exists at a ratio of 10 weight % or higher in the entire hydrogen absorbing alloy and yttrium is contained at a ratio of 2 mol % or more and 10 mol % or less in the entire hydrogen absorbing alloy.

Abstract: A sealed alkaline storage battery including a nickel electrode as a positive electrode, characterized by having the function of being capable of charge when the gas pressure in the battery and/or the battery temperature is not higher than a specified value and of being incapable of charge when the gas pressure in the battery and/or the battery temperature exceeds the specified value.