# Effect of copper additive on $Zr_{0.9}Ti_{0.1}V_{0.2}Mn_{0.6}Cr_{0.05}Co_{0.05}Ni_{1.2}$ alloy anode for nickel-metal hydride batteries

Hariprakash, B and Martha, SK and Shukla, AK (2003) Effect of copper additive on $Zr_{0.9}Ti_{0.1}V_{0.2}Mn_{0.6}Cr_{0.05}Co_{0.05}Ni_{1.2}$ alloy anode for nickel-metal hydride batteries. In: Journal of Applied Electrochemistry, 33 (6). pp. 497-504.

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## Abstract

The $Zr_{1-x}Ti_xV_{0.2}Mn_{0.6}Cr_{0.05}Co_{0.05}Ni_{1.2}$ $(0\leq x \leq 0.3)$ alloys have been characterized as metal-hydride electrodes for nickel-metal hydride batteries. Although the alloy electrodes with no Ti substitution in place of Zr exhibit a specific capacity value of $375 \hspace{2mm} mA \hspace{2mm} h \hspace{2mm} g^{-1}$ it has been possible to enhance the specific capacity of the electrodes to $395 \hspace{2mm} mA \hspace{2mm} h \hspace{2mm} g^{-1}$ by substituting 10% Ti in place of Zr, that is, with $Zr_{0.9}Ti_{0.1}V_{0.2}Mn_{0.6}Cr_{0.05}Co_{0.05}Ni_{1.2}$ alloy. The specific capacity value of $Zr_{0.9}Ti_{0.1}V_{0.2}Mn_{0.6}Cr_{0.05}Co_{0.05}Ni_{1.2}$ alloy was further enhanced to $415 \hspace{2mm} mA \hspace{2mm} h \hspace{2mm} g^{-1}$ on copper powder addition. Interestingly, the discharge curves for the latter electrode are quite flat thus providing an advantage of constant specific energy output over the entire regime of electrode discharge. Both a.c. impedance and d.c. linear polarization studies conducted on these electrodes lead to a lower charge-transfer resistance value for the metal-hydride electrode with copper additive suggesting the electrode with copper powder additive to have a higher catalytic activity than those without copper. The electrode with the copper additive also exhibits little change in its capacity over about 100 charge-discharge cycles.

Item Type: Journal Article Copyright of this article belongs to Kluwer Academic Publishers. AB2 alloy;a.c. impedance;Nickel–metal hydride batteries Division of Chemical Sciences > Solid State & Structural Chemistry Unit 30 Jun 2008 19 Sep 2010 04:37 http://eprints.iisc.ernet.in/id/eprint/10725