Providing A Long-term Protection for NCM811 Cathode Material by Al2O3 Coating Layer

Abstract

The degradation of Ni-rich LiNi0.8Co0.1Mn0.1O2 cathode material is successfully suppressed via a facile Al2O3 coating method. The coated Al2O3 layer on the electrode surface is inactive and amorphous, it does not react with the electrolyte and could provide a long-term protection on the electrode during cycling. The electrochemical performance of the modified NCM811 was improved dramatically both at room and elevated temperature. The capacity retention of pristine NCM811 was enhanced from 81.8% to 91.7% when the coating amount reached to 2 wt% at 25°C and much increased from 68.5% to 87.7% at 55°C. Such excellent high temperature performance clearly confirmed the effect of Al2O3 on the structure stability of electrode, it successfully built a favorable protection of the bulk NCM811 from direct contact with electrolyte and suppressed the undesired side reactions.