Manganese-free rare earth-transition metal AB¿5?-type hydrogen-absorbing alloys having favorable high rate discharge characteristics, suitable for use in rechargeable batteries for electrical vehicles or hybrid electrical vehicles, include compositions of the general formula: R(Co¿u?Al¿v?M¿w?Ni¿l-u-v-w?)¿z?, where R is at least one element selected from rare earth elements and yttrium (Y), M is at least one refractory metal selected from Groups IVB, VB, and VIB of the periodic table, the value of u is from 0 to about 0.25, v is from 0 to about 0.10, w is from 0 to about 0.05, and z, the ratio of R(Co¿u?Al¿v?M¿w?Ni¿l-u-v-w?)/R, is from about 4.70 to about 5.50. The unit cell volume is from about 87 to about 88.5 A?3¿ at 25 °C, the plateau pressure is from about 3 to about 10 apsi at 25 °C, and the composition is essentially free of manganese. The figure shows a schematic diagram of the measurement of a Pressure Composition Isotherm (PCT) in a Sievert-type-gas-solid reactor.

Title
Ab¿5?-type rare earth transition intermetallic compounds for the negative electrodes of rechargeable batteries
Application Number
PCT/US2000/001758
Publication Number
2000/044951
Application Date
January 27, 2000
Publication Date
August 3, 2000
Inventor
Chen Qun
Landi James
Ma Bao Min
Perng Tsong P
Agent
VENTURINO Anthony P
Assignee
Santoku Corporation
IPC
H01M 04/38
C22C 28/00
C01B 03/00
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