Synthesis and characterization of submicron size particles of $LiMn_{2}O_{4 }$by microemulsion route

Sinha, Nupur Nikkan and Munichandraiah, N (2008) Synthesis and characterization of submicron size particles of $LiMn_{2}O_{4 }$by microemulsion route. In: Journal of Solid State Electrochemistry, 12 (12). 12:1619-1627.

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Abstract

Among the various positive electrode materials investigated for $Li^-ion$ batteries, spinel $LiMn_{2}O_{4}$ is one of the most important materials. Small particles of the active materials facilitate high-rate capability due to large surface to mass ratio and small diffusion path length. The present work involves the synthesis of submicron size particles of $LiMn_{2}O_{4}$in a quaternary microemulsion medium. The precursor obtained from the reaction is heated at different temperatures in the range from 400 to 900 °C. The samples heated at 800 and 900 °C are found to possess pure spinel phase with particle size <200 nm, as evidenced from XRD, SEM, and TEM studies. The electrochemical characterization studies provide discharge capacity values of about 100$ mAh g^{−1}$ at C/5 rate, and there is a moderate decrease in capacity by increasing the rate of charge–discharge cycling. Studies also include charge–discharge cycling and ac impedance studies in temperature range from −10 to 40 °C. Impedance data are analyzed with the help of an equivalent circuit and a nonlinear least squares fitting program. From temperature dependence of charge-transfer resistance, a value of 0.62 eV is obtained for the activation energy of $Mn^{3+}/Mn^{4+}$ redox process, which accompanies the intercalation/deintercalation of the $Li^+ ion$ in$LiMn_{2}O_{4}$.

Item Type:	Journal Article
Publication:	Journal of Solid State Electrochemistry
Publisher:	Springer
Additional Information:	copyright of this article belongs to Springer
Keywords:	LiMn2O4 cathode material;Microemulsion; Cyclic voltammetry; Charge–discharge cycling; ac impedance
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	19 Dec 2008 18:21
Last Modified:	19 Sep 2010 04:52
URI:	http://eprints.iisc.ac.in/id/eprint/16467

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