A nickel-hydrogen secondary battery includes an electrode group that includes a separator, a positive electrode and a negative electrode, and the negative electrode contains a hydrogen storage alloy having a crystal structure in which an AB.sub.2 type unit and an AB.sub.5 type unit are laminated, in which a PCT characteristic diagram at 80 C. includes a first plateau region having a hydrogen pressure Pd1 when hydrogen is stored by 0.25 times an effective hydrogen storage amount that is a hydrogen storage amount when a hydrogen pressure is 1 MPa, and a second plateau region having a hydrogen pressure Pd2 when hydrogen is stored by 0.70 times the effective hydrogen storage amount, and Pd1 and Pd2 satisfy a relation of 0.6log.sub.10(Pd2/Pd1).

Heterogeneous metal hydride (MH) compositions comprising a main region comprising a first metal hydride and a secondary region comprising one or more additional components selected from the group consisting of second metal hydrides, metals, metal alloys and further metal compounds are suitable as anode materials for lithium ion cells. The first metal hydride is for example MgH.sub.2. Methods for preparing the composition include coating, mechanical grinding, sintering, heat treatment and quenching techniques.

An electrochemical direct heat to electricity converter includes a primary thermal energy source; a working fluid; an electrochemical cell comprising at least one membrane electrode assembly including a first porous electrode, a second porous electrode and at least one membrane, wherein the at least one membrane is sandwiched between the first and second porous electrodes and is a conductor of ions of the working fluid; an energy storage reservoir; and an external load. The electrochemical cell operates on heat to produce electricity. When thermal energy available from the primary thermal energy source is greater than necessary to meet demands of the external load, excess energy is stored in the energy storage reservoir, and when the thermal energy available from the primary thermal energy source is insufficient to meet the demands of the external load, at least a portion of the excess energy stored in the energy storage reservoir is used to supply power to the external load.

A layer cell includes an outer casing, a positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode, and an electrically conductive current collector passing through the positive electrode, the negative electrode and the separator in an axial direction of the outer casing. The positive electrode, the negative electrode and the separator are stacked in the axial direction of the outer casing. A first electrode which is one of the positive electrode and the negative electrode is in contact with an inner surface of the outer casing, but is not in contact with the current collector. A second electrode which is the other electrode is not in contact with the outer casing, but is in contact with the current collector. An outer edge of the second electrode is covered with the separator. A peripheral edge of a hole, through which the current collector passes, in the first electrode is covered with the separator.

The present disclosure relates to improved processes for the preparation of metal hydrides. The present disclosure also relates to metal hydrides, e.g., metal hydrides prepared by the processes described herein, that exhibit enhanced hydrogen storage capacity when used as hydrogen storage systems.

In at least one embodiment, a method of scavenging hydrogen in a lithium-ion battery is provided. The method may comprise including an atomic intermetallic material in at least one of a positive electrode or a negative electrode of a lithium-ion battery and reacting hydrogen present inside the lithium-ion battery with the atomic intermetallic material to form a metal hydride. The method may include preparing a positive electrode slurry and a negative electrode slurry, each slurry including an active material and a binder, mixing an atomic intermetallic material including a proton absorbed state into at least one of the slurries, and casting the slurries to form a positive electrode and a negative electrode. The method may alternately include applying an atomic intermetallic material including a proton absorbed state to a surface of at least one of a lithium-ion battery positive electrode or negative electrode.

Provided is an alloy powder for an electrode which enables an alkaline storage battery to have both excellent discharge characteristics and excellent life characteristics. The alloy powder includes a hydrogen storage alloy including an element L, Mg, Ni, Al, and an element M.sup.a. The element L is at least one selected from the group consisting of group 3 elements and group 4 elements of the periodic table (excluding Y). The element M.sup.a is at least two selected from the group consisting of Ge, Y, and Sn. A molar proportion x of Mg in a total of the element L and Mg is 0.008x0.54. A molar proportion y of Ni, a molar proportion of Al, and a molar proportion of the element M.sup.a, per the foregoing total is 1.6y4, 0.0080.32, and 0.010.12, respectively.

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.

Disclosed herein is a regeneration method of a nickel-hydrogen battery provided with a positive electrode at least including nickel hydroxide. In the regeneration method, a regeneration process of charging a nickel-hydrogen battery is performed by supplying a square-wave pulse current set to a repetition frequency ranging from 5 kHz to 10 kHz and to an average value of current I.sub.AVE ranging from 1 A to 10 A.

A battery negative electrode includes a hydrogen storage alloy as a negative electrode active material, wherein the hydrogen storage alloy has a mean volume diameter within a range from 4 m to 12 m, and is disposed to be capable of being in contact with hydrogen in a hydrogen containing part in which hydrogen is contained.