Effect of interface modifications on voltage fade in 0.5Li2MnO3·0.5LiNi0.375Mn0.375Co0.25O2 cathode materials

The effects of the coatings Al2O3, LiAlOx, ZrO2, TiO2, AlPO4, and LiPON and of the electrolyte additives 3-hexylthiophene and lithium difluoro (oxalato)borate (LiDFOB) on the voltage fade phenomenon in 0.5Li2MnO3·0.5LiNi0.375Mn0.375Co0.25O2 cathodes were investigated. Cells containing these materials or additives were cycled according to a standard protocol at room temperature between 2.0 and 4.7 V vs. Li+/Li. As expected, the cells containing either an additive or a coated cathode displayed less capacity loss than cells containing an uncoated cathode and no additive. The voltage fade phenomenon was quantified in terms of changes in the average cell voltage (Wh/Ah). The results indicate that, within experimental error, all of the coatings and additives produced little-to-no effect on voltage fade.