Raja, M W and Mahanty, Sourindra and Basu, Rajendra Nath (2009) Multi-faceted highly crystalline LiMn(2)O(4) and LiNi(0.5)Mn(1.5)O(4) cathodes synthesized by a novel carbon exo-templating method. Solid State Ionics, 180 (23-25). pp. 1261-1266. ISSN 0167-2738

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LiMn(2)O(4) and LiNi(0.5)Mn(1.5)O(4) powders have been synthesized by a novel cost-effective carbon exo-templating process. It has been observed that controlled nucleation in the pores of highly surface active carbon produces a distinct effect on the powder morphology and crystallinity. Quantitative X-ray phase analyses show single phase spinel structure having Fd3m symmetry for both samples. Field emission electron microscopy reveals particles of size 0.5-1.0 mu m with well defined multi-faceted crystals. Cyclic voltammetry results show well separated distinct redox peaks at 4.05/3.92 and 4.17/4.08 V for LiMn(2)O(4)/Li and 4.91/4.61 V for LiNi(0.5)Mn(1.5)O(4)/Li coin cells indicating good crystallinity and reversibility of the cathodes compared to that of pristine LiMn(2)O(4) synthesized by conventional combustion process. The LiMn(2)O(4)/Li and LiNi(0.5)Mn(1.5)O(4)/Li cells deliver an initial discharge capacity of 110 mA h/g and 122 mA h/g respectively at a current density of 0.05 mA/cm(2) and when cycled at 0.2 mA/cm(2), the cells maintain 81% and 96% of their initial discharge capacity respectively even after 20 cycles. On the other hand, at the same current density, LiMn(2)O(4) synthesized by conventional combustion process suffers from severe capacity fading (only 37.5% capacity retention after the 25th cycle). The capacity fading rate is found to be very less even at further higher current densities (0.4-0.8 mA/cm(2)) for both LiMn(2)O(4)/Li and LiNi(0.5)Mn(1.5)O(4)/Li cells synthesized by the templating process. The present study reveals that high crystallinity along with multi-faceted morphology shows a remarkable enhancement in capacity as well as rate performance of pristine LiMn(2)O(4) and its Ni derivative. (C) 2009 Elsevier B.V. All rights reserved.

Item Type: Article
Uncontrolled Keywords: Lithium-ion battery; Lithium manganese oxide; Templating; Microstructure; Electrochemical properties
Subjects: Electronics
Divisions: Fuel Cell and Battery
Depositing User: Bidhan Chaudhuri
Date Deposited: 01 Mar 2012 07:54
Last Modified: 01 Mar 2012 07:54
URI: http://cgcri.csircentral.net/id/eprint/1086

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