Cyclability and dissolution of manganese in substituted stoichiometric andnon-stoichiometric lithium manganese oxides at high temperature

The cyclability of substituted stoichiometric spinels LiM1.6Mn11.6O4 (M =Al , Co and Ni) has been investigated in the cell Li \ 1 mol dm(-3) LiClO4 + E C-DEC \ LiM1.6M11.6O4 at 50 degrees C. The amount of manganese dissolved in to the electrolyte from the spinel was measured at different cycle interval s by ICP technique. It was found that the capacity loss was considerably re duced in the case of substituted spinel compared to the parent one even at elevated temperature. Among these substituted compounds, the Ni-substituted spinel exhibited good capacity retention behavior with minimum loss of cap acity followed by Go-substituted one. Non-stoichiometric spinels with metal excess structure which written as Li[M-excess](16c)[M1.6Mn11.6](16d)O-4 (M ' = Li, Mn, M; M =Al, Ni) were synthesized under reduced partial pressure c onditions. These compounds were observed to possess higher capacity and goo d cyclability in spite of their higher manganese dissolution over their cor responding stoichiometric counterparts.