Consumption reduction of AB5 alloy in Ni–MH battery by the use of cobalt oxyhydroxide coated nickel hydroxide

Regulation of the discharge reservoir of negative electrodes in Ni–MH batteries by using Ni(OH) (x= 2.10) and γ-CoOOH

“…On the one hand, R dis-1 is completely removed from the metal hydride electrodes by the use of ␥-CoOOH, similar to that of Ni(OH) 2 coated with CoOOH [9]. For the batteries mixed with CoO, the R dis-1 equals the electric quantity consumed during the formation of CoOOH.…”

“…In addition, it can be seen that batteries B and C at 100% DOD exhibit a lower inner resistance of 11.9 and 11.7 m, whereas the value for the normal battery A is 13.2 m. This can be attributed to the preferable conductivity of the adding compounds in the positive electrode. It may also result from a decrease in the internal resistance of the MH electrode with the reduction of R dis , since the electric conductivity of the hydrogen-absorbing alloy (M) is much higher than that of metal hydride (MH) [9]. Compared battery A with B, It can be concluded that the electrochemical performance improvement of the discharge capacity, high-rate discharge ability, and high discharge potential plateau is due to the addition of Ni(OH) x (x = 2.10) and ␥-CoOOH.…”

“…Recently, Li et al [9] have reported a method to reduce the consumption of AB 5 alloy in a Ni-MH battery by using cobalt oxyhydroxide coated nickel hydroxide. However, the R dis-1 of only about 8% of the capacity of the positive electrode was removed from the metal hydride electrodes by this method and the R dis-2 obtained from the incomplete reversible reaction (2) was not taken into account.…”

Study on self-discharge property of Nd0.88Mg0.12Ni3.10+xAl0.20 (x=0.00, 0.10, 0.20, 0.30) hydrogen storage alloys

“…The 24-h charge retention rate (CRT) of alloy electrode increases first from 22.5% (x = 0.00) to 82.1% (x = 0.20), and then decreases to 33.2% (x = 0.30) with increasing x at 318 K. Pressure-composition-temperature (P-C-T) tests indicate that the plateau pressure first decreases and then increases with increasing Ni content, implying that the stability of the hydride first increases and then decreases. FESEM-EDS and XRD show that Mg(OH) 2 and Nd(OH) 3 are formed on surface of the alloy particles, which causes irreversible capacity loss. Tafel polarization curves suggest that the alloy electrode (x = 0.20) has a lower corrosion rate.…”

“…The nickel/metal hydride (Ni/MH) batteries using hydrogen storage alloys as negative electrode materials have recently been considered as promising power sources for their environmental compatibility, high specific energy and power, long life and good security [1,2]. However, the Ni/MH batteries suffer from high selfdischarge rate, which is unsatisfactory for industrial application [3].…”