Ghosh, Paromita and Mahanty, Sourindra and Basu, Rajendra Nath (2009) Improved Electrochemical Performance of Li(2)MnSiO(4)/C Composite Synthesized by Combustion Technique. Journal of the Electrochemical Society, 156 (8). A677-A681. ISSN 0013-4651

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Abstract

Li(2)MnSiO(4) cathode powders were synthesized by a simple combustion technique using citric acid as a chelating agent. The as-synthesized powder was ballmilled with acetylene black (0-20 wt %) and heated at 700 degrees C in argon atmosphere to form a Li(2)MnSiO(4)/C composite. X-ray powder diffraction indicated the formation of Li(2)MnSiO(4) possessing an orthorhombic crystal structure along with manganese oxide as a minor impurity phase. Field-emission-scanning electron microscopy showed that pristine Li(2)MnSiO(4) consists of large agglomerates of similar to 500 to 800 nm. The addition of acetylene black resulted in a drastic change in morphology for Li(2)MnSiO(4)/C composites consisting of uniform grains of similar to 50 nm. The electrochemical discharge capacity as well as the rate capability of Li(2)MnSiO(4) also improved dramatically with an increasing amount of conducting carbon (acetylene black) in the matrix, and a value as high as 164 mAh g(-1) was obtained at a current density of 0.01 mA/cm(2). Impedance spectroscopy showed that the addition of acetylene black decreases the charge-transfer impedance and checks the growth of cell impedance during cycling. Cyclic voltammetry showed two oxidation/reduction couples at 3.6/2.9 and 4.5/4.3 V with good reversibility.

Item Type:	Article
Uncontrolled Keywords:	Ball milling; Carbon; Combustion synthesis; Composite materials; Crystal structure; Current density; Electrochemical electrodes; Field emission electron microscopy; Grain size; Lithium compounds; Manganese compounds; Oxidation; Powders; Reduction (chemical); Scanning electron microscopy; Voltammetry (chemical analysis); X-ray diffraction
Subjects:	Electronics
Divisions:	UNSPECIFIED
Depositing User:	Ashok K Podder
Date Deposited:	22 Feb 2012 05:35
Last Modified:	22 Feb 2012 05:35
URI:	http://cgcri.csircentral.net/id/eprint/984

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