Facile and efficient fabrication of Li3PO4-coated Ni-rich cathode for high-performance lithium-ion battery

Owing to their low cost and high theoretical specific capacity, layered Ni-rich materials are extensively investigated as promising cathode materials for lithium-ion batteries. However, most Ni-rich materials do not exhibit superior cycle and rate capabilities at a high voltage or after exposure to air. In this study, Li3PO4-coated LiNi0.8Co0.1Mn0.1O2 ([email protected]) is developed using a simple one-pot sol–gel method by immersing NCM powder in a hydrophobic solution. Unlike the commonly used wet-coating method, the Li3PO4 coating layer is produced in situ on the NCM surface via precipitation reaction between polyphosphoric acid and residual Li compounds without additional re-heating. The Li-conductive Li3PO4 shield diminishes the electrode–electrolyte contact and suppresses the side reactions. Thus, the [email protected] sample shows a high capacity retention rate of 88.4% after 100 cycles at 1 C and an excellent capacity of 148.8 mAh g−1 at 10 C. Furthermore, the capacity retention rate of [email protected] sample is still as high as 84.6% after 100 cycles at 1 C after exposed in air for 7 days, which is much higher than that of the pristine NCM. The facile and efficient approach can be used to boost the cycle stability and inhibit the air sensitivity of other Ni-based cathode materials.