Significance of the Tetrahedral A Site on the Electrochemical Performance of Substituted Li[sub 1.05]M[sub 0.05]Mn[sub 1.90]O[sub 4] Spinel Electrodes (M=Li, Mg, Zn, Al) in Lithium Cells

The electrochemical performance of substituted spinel electrodes 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 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.