High structural stability and Li-conduction of LiNi0.8Co0.1Mn0.1O2 cathode co-coated by Al2O3 and LiNbO3 for high performance lithium-ion battery

Lithium-ion batteries (LIBs) hold promise for revolutionizing the next generation of battery systems due to the utilization of high specific capacity LiNixCoyMn1−x−yO2 (NCM) cathode materials. However, despite extensive research efforts towards further commercialization of NCM across various fields, challenges persist, particularly related to structural instability and side reactions with liquid electrolytes, resulting in inevitable capacity fade during cycling. In this study, we present a facile surface co-coating method for polycrystalline LiNi0.8Co0.1Mn0.1O2 (NCM811), employing stable, cost-effective Al2O3 and lithium-ion conductive LiNbO3. While Al2O3 provides a specific enhancement to create a durable coating layer, LiNbO3 is well known as the high ion-conductive coating layer. Owing to the synergistic effects of the co-coating layer with an optimal coating amount, Al2O3–LiNbO3 co-coated NCM exhibited excellent electrochemical properties. At a loading level of 3 g cm−3, it achieves a discharge capacity of 187.35 mA h g−1 at 0.2C and 76.53 mA h g−1 at 5C. Furthermore, the retention rate of Al2O3–LiNbO3 co-coated NCM reaches 92.51% at 0.5C after 100 cycles, compared to only 87.70% of the uncoated NCM. Our study demonstrates the significant improvement in the electrochemical performance of NCM facilitated by the Al2O3–LiNbO3 co-coating, surpassing single-coating strategies.