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Electrochemical Characterization of Submicron Size Particles of $LiMn_2O_4$ in Aqueous Electrolytes

Sinha, Nupur Nikkan and Ragupathy, P and Vasan, HN and Munichandraiah, N (2008) Electrochemical Characterization of Submicron Size Particles of $LiMn_2O_4$ in Aqueous Electrolytes. In: International Journal of Electrochemical Science, 3 (6). pp. 691-710.

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Abstract

Spinel $LiMn_2O_4$ is synthesized by inverse microemulsion route and particles of size less than 200 nm are obtained. The electrochemical characterization of the sub-micron size particles of $LiMn_2O_4$ is carried out in an aqueous solution of 5 M $LiNO_3$. In cyclic voltammetry, $LiMn_2O_4$ electrodes exhibit two pairs of reversible redox peaks and accordingly separate potential plateaus are observed during charge-discharge cycling. Electrochemical impedance data measured at various temperatures and various state-of-charge (SOC) values are analyzed to calculate exchange current, activation energy and transfer coefficient for $Mn^{4+}/Mn^{3+}$ redox process in $LiMn_2O_4$, which accompanies intercalation/deintercalation of $Li^+$ ions. Impedance data are subjected to non-linear least squares fit procedure using an appropriate electrical equivalent circuit and charge-transfer resistance ($R_{ct}$) of the redox process is evaluated. The kinetic parameters of the process are calculated from variations of $R_{ct}$ with temperature and SOC of $LiMn_2O_4$ electrode in 5 M $LiNO_3$ aqueous electrolyte. A typical cell employing $LiMn_2O_4$ as the positive electrode and $V_2O_5$ as the negative electrode was assembled and characterized by charge-discharge cycling in 5 M $LiNO_3$ aqueous electrolyte.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to Electrochemical Science Group.
Keywords: LiMn2O4;sub-micron size particles;microemulsion route;aqueous electrolyte.
Department/Centre: Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited: 07 Jul 2008
Last Modified: 19 Sep 2010 04:47
URI: http://eprints.iisc.ernet.in/id/eprint/14824

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