Significance of the Tetrahedral A Site on the Electrochemical Performance of Substituted Li_1.05M_0.05Mn_1.90O₄ Spinel Electrodes (M = Li, Mg, Zn, Al) in Lithium Cells

J.-S. Kim, J. T. Vaughey, C. S. Johnson, and M. M. Thackeray

Electrochemical Technology Program, Chemical Engineering Division Argonne National Laboratory, Argonne, IL USA

The electrochemical performance of substituted Li_1.05M_0.05Mn_1.90O₄ spinel electrodes (M = Li, Mg, Zn, Al) in lithium cells has been studied as a function of the oxidation states of the M and Mn ions in the parent electrode, and the occupancy of the tetrahedral A sites by the Li and the M ions. At 5% substitution of manganese, neutron diffraction analyses show that the M ions reside at the A sites of the A[B₂]O₄ spinel structure. The electrochemical data showed that at 50°C the rate of capacity fade can be correlated with the M-ion occupancy of the A sites. A possible explanation for this phenomenon is provided.

Copyright © 2004, The Electrochemical Society, Inc.

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