Raju, M. and Manimaran, K. and Ananth, M.V. and Renganathan, N.G. (2007) An EIS study on the capacity fades in MmNi3.6Al0.4Mn0.3Co0.7 metal-hydride electrodes. International Journal of Hydrogen Energy , 32. 1721 -1727. ISSN 0360-3199

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Abstract

Capacity fade, generally observed in metal-hydride electrodes of nickel metal-hydride batteries with prolonged cycling, is a problem of concern. To investigate the capacity fade, electrochemical impedance spectroscopy (EIS) measurements were performed in lanthanum rich mischmetal alloy (MmNi3.6Al0.4Mn0.3Co0.7) electrodes. The impedance measurements were conducted during charging at different stages of cycle life. A novel approach was made to get reaction resistances and limiting currents from impedance data based on an equivalent circuit for finite spherical hydrogen diffusion. The main cause of the capacity fade occurring in metal-hydride electrodes with number of cycles was due to particle pulverization and consequent poor hydrogen desorption kinetics, thereby making it more difficult for hydrogenation to occur because of passivation and resistance of electron conduction between the alloy particles.

Item Type:	Article
Uncontrolled Keywords:	Hydrogen storage alloys; Ni/MH batteries; Cyclic stability; Impedance measurements; Electrochemical kinetics
Subjects:	Electrochemical Power Sources
Divisions:	UNSPECIFIED
Depositing User:	ttbdar CECRI
Date Deposited:	26 Mar 2012 12:53
Last Modified:	26 Mar 2012 12:53
URI:	http://cecri.csircentral.net/id/eprint/703

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