ELECTRODE MATERIALS FOR THE ANODES OF NICKEL-METAL-HYDRIDE RECHARGEABLE BATTERIES - THE ELECTRODES BASED ON SUBSTITUTED COMPOUNDS OF THE AB(5) TYPE

The discharge capacity of electrode materials based on the LaNi2.5Co2. 5, LaNi2.5Co2.4Mn0.1, La0.8Ce0.2Ni2Co3, La0.7Nb0.3Ni2.5Co2.4Cr0.1, MmN i(3.5)Co(0.7)Al(0.8), and Mm(0.5)La(0.5)Ni(2)Co(3) intermetallic compo unds (IMC) with copper and polytetrafluoroethylene binders is determin ed. The IMC hydrides, which are stable at room temperature and atmosph eric pressure in 1 M NaOH, are shown to contain 2.4 to 4.2 hydrogen at oms per each formula unit of the alloys. It is established that a part ial replacement of La with Ce makes no impact on the capacity and life time of the electrodes. Introducing Nb into the alloys and increasing La content in a mixture of rare-earth metals make the discharge capaci ty of the electrodes significantly diminish. Activation modes precedin g the measurements are suggested. The overvoltage during the electrode discharge and the capacity attained during this process are found to be determined by the binder nature rather than the alloy nature. At th e same discharge currents, the overvoltage is lower and the capacity i s higher for the electrodes with the Cu binder. The La0.8Ce0.2Ni2Co3 a nd MmNi(3.5)Co(0.7)Al(0.8) alloys offer promise as metal-hydride anode s of nickel-metal-hydride rechargeable batteries.