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Variations of the electrochemical properties of LiMn2O4 with synthesis conditions
LiMn2O4 samples were prepared by solid-state reaction at various temperatures between 650 and 900 C from LiOH and MnO2 (chemical manganese dioxide, CMD). Other samples were also prepared at 750 C with a different cooling rate, or for different periods of time (24 and 72 h), with the other conditions...
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Published in: | Journal of the Electrochemical Society 2000-03, Vol.147 (3), p.874-879 |
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Main Authors: | , |
Format: | Article |
Language: | English |
Subjects: | |
Online Access: | Get full text |
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Summary: | LiMn2O4 samples were prepared by solid-state reaction at various temperatures between 650 and 900 C from LiOH and MnO2 (chemical manganese dioxide, CMD). Other samples were also prepared at 750 C with a different cooling rate, or for different periods of time (24 and 72 h), with the other conditions being identical. XRD patterns of the samples are identified as the spinel structure with a space group Fdbar3m. The lattice parameter increases gradually as the sintering temperature rises. The potential vs lithium ion concentration curves exhibit two distinct plateaus. The sample sintered at 750 C for 48 h (intermediately cooled at a rate of 1 C/min) has the largest first discharge capacity and shows the best cycling performance. It is believed that the best electrochemical properties of this sample result from its crystallinity and large grain size compared with other samples. The particles are relatively large and uniform in size. The crystallinity of the prepared samples was studied using a "crystallinity index" Imax/B, where Imax is the maximum intensity of the diffraction peak considered, and B is the width at an intensity equal to half Imax. 15 refs. |
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ISSN: | 0013-4651 1945-7111 |
DOI: | 10.1149/1.1393285 |