An alkaline secondary battery includes at least a positive electrode, a negative electrode, and an electrolytic solution. The positive electrode includes at least one of manganese oxyhydroxide and manganese dioxide. The negative electrode includes a hydrogen storage alloy.

Disclosed is an alloy powder for electrodes for nickel-metal hydride storage batteries having a high battery capacity and being excellent in life characteristics and high-temperature storage characteristics. The alloy powder includes a hydrogen storage alloy containing elements L, M, Ni, Co, and E. L includes La as an essential component. L includes no Nd, or when including Nd, the percentage of Nd in L is less than 5 mass %. The percentage of La in the hydrogen storage alloy is 23 mass % or less. M is Mg, Ca, Sr and/or Ba. A molar ratio to a total of L and M is 0.0450.133. A molar ratio x of Ni to the total of L and M is 3.5x4.32, and a molar ratio y of Co is 0.13y0.5. The molar ratios x and y, and a molar ratio z of E to the total of L and M satisfy 4.78x+y+z<5.03.

A nickel-metal hydride battery is provided with a positive electrode and a negative electrode including hydrogen absorbing alloys. The hydrogen absorbing alloys of the negative electrode include a first hydrogen absorbing alloy and a second hydrogen absorbing alloy having a higher hydrogen equilibrium dissociation pressure than the first hydrogen absorbing alloy. Each hydrogen absorbing alloy includes an element A having high affinity for hydrogen and an element B having low affinity for hydrogen. The ratio of a substance amount of the element B to a substance amount of the element A is greater in the second hydrogen absorbing alloy than the first hydrogen absorbing alloy.

A hydride secondary battery includes: a pressure vessel; a positive electrode disposed in the pressure vessel; a negative electrode disposed in the pressure vessel; and hydrogen gas with which the pressure vessel is filled. The negative electrode contains a hydrogen-absorbing alloy. In a pressure-composition-temperature diagram, a desorption curve at 25 C. of the hydrogen-absorbing alloy has a plateau pressure of 0.15 MPa or more and 10 MPa or less. The hydrogen gas has a pressure equal to or higher than the plateau pressure at 25 C. of the hydrogen-absorbing alloy.

A hydrogen-absorbing alloy included in alloy powder for electrodes includes elements L, elements M, Ni, Co, and elements E. L include La as an essential component. L do not include Nd, or, even when L include Nd, the percentage of Nd in L is 5 mass % or less. Furthermore, M include at least Mg, E include at least Mn, and molar ratio .sub.1 of Mg to the sum total of L and M satisfies 0.000<.sub.10.050. Molar ratio x of Ni to the sum total of L and M satisfies 3.50x4.32, and molar ratio y of Co to the sum total of L and M satisfies 0.13y0.50. Molar ratio x, molar ratio y, and molar ratio z of E satisfy 4.78x+y+z<5.03, and ratio y/ of molar ratio y to molar ratio that is the ratio of Mn to the sum total of L and M satisfies 0.80y/1.50.

Organosilicon electrolytes exhibit several important properties for use in lithium carbon monofluoride batteries, including high conductivity/low viscosity and thermal/electrochemical stability. Conjugation of an anion binding agent to the siloxane backbone of an organosilicon electrolyte creates a bi-functional electrolyte. The bi-functionality of the electrolyte is due to the ability of the conjugated polyethylene oxide moieties of the siloxane backbone to solvate lithium and thus control the ionic conductivity within the electrolyte, and the anion binding agent to bind the fluoride anion and thus facilitate lithium fluoride dissolution and preserve the porous structure of the carbon monofluoride cathode. The ability to control both the electrolyte conductivity and the electrode morphology/properties simultaneously can improve lithium electrolyte operation.

A carbothermic reduction method is provided for reducing a La-, Ce-, MM-, and/or Y-containing oxide in the presence of carbon and a source of a reactant element comprising Si, Ge, Sn, Pb, As, Sb, Bi, and/or P to form an intermediate alloy material including a majority of La, Ce, MM, and/or Y and a minor amount of the reactant element. The intermediate material is useful as a master alloy for in making negative electrode materials for a metal hydride battery, as hydrogen storage alloys, as master alloy additive for addition to a melt of commercial Mg and Al alloys, steels, cast irons, and superalloys; or in reducing Sm.sub.2O.sub.3 to Sm metal for use in SmCo permanent magnets.

A nickel hydrogen secondary battery includes an outer can and an electrode group accommodated in the outer can in a sealed state together with an alkaline electrolyte. The electrode group includes a positive electrode and a negative electrode having a separator sandwiched therebetween, the alkaline electrolyte includes NaOH as the main solute, and the negative electrode includes a hydrogen storage alloy having a composition represented by a general formula: Ln.sub.1-xMg.sub.xNi.sub.y-zM.sub.z, wherein Ln is at least one element selected from rare earth elements and Zr; M is Al; subscripts x, y and z satisfy the following relations, respectively: 0x0.05, 3.3y3.6, and 0z0.50; and the content of La among rare earth elements in Ln is 25% or less.

It is an object of the present invention to improve the cycle performance in a nickel-metal hydride battery using a rare earth-MgNi type alloy. The present invention provides a nickel-metal hydride battery having a negative electrode including an LaMgNi based hydrogen absorbing alloy, wherein the hydrogen absorbing alloy has a crystal phase having Gd.sub.2Co.sub.7 type crystal structure and contains calcium.

A nickel hydrogen secondary battery accommodates an electrode group including a positive electrode and a negative electrode which are stacked one on top of another through a separator, together with an alkaline electrolyte. The battery contains Li, with a total amount of Li in the battery 2 of 15 to 50 mg/Ah, as determined as the mass in terms of LiOH per Ah of the positive electrode capacity. The negative electrode includes particles of rare earth-MgNi-based hydrogen storage alloy which contains a rare earth element, Mg and Ni. The hydrogen storage alloy particles 44 includes, on the surface thereof, a rare earth hydroxide which is the hydroxide of a rare earth element and has a specific surface area of 0.1 to 0.5 m.sup.2/g.