Structural Fatigue in Spinel Electrodes in High Voltage (4 V) Li/Li[sub x]Mn[sub 2]O[sub 4] Cells

Evidence of structural fatigue has been detected at the surface of discharged Lix[Mn2]O4 spinel electrodes in (4 V) Li/Lix[Mn2]O4 cells. Under nonequilibrium conditions, domains of tetragonal Li2[Mn2]O4 coexist with cubic Li[Mn2]O4, even at 500 mV above the thermodynamic voltage expected for the onset of the tetragonal phase. The presence of Li2[Mn2]O4 on the particle surface may contribute to some of the capacity fade observed during cycling of Li/Lix[Mn2]O4 cells.