Ni-rich cathode is one of the promising candidate for high-energy lithium-ion batteries. In this work, we prepare the different super-P carbon black amounts [0.1 (SPB 0.1 wt%), 0.3 (SPB 0.3 wt%), 0.5 (SPB 0.5 wt%) and 0.7 wt% (SPB 0.7 wt%)] of carbon coated LiNi0.8Co0.1Mn0.1O2 (NCM811) cathodes and their electrochemical performances are investigated. Carbon coating does not change the crystal structure and morphology of NCM811. Among the coated NCM811, the SPB 0.5 wt% NCM811 delivers the excellent cyclability (87.8% after 80 cycles) and rate capability (86.5% at 2 C) compared to those of pristine NCM811. It is ascribed to that the carbon coating not only increase the Li ion and electron transfer as well as protect the NCM811 cathode materials from side reaction at the electrolyte/NCM811 interface. Therefore, we can conclude that the appropriate amount of carbon coating can be regarded as an effective approach for Ni-rich NCM cathode.

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In this study, lithium phosphate (Li3PO4) is coated on the surface of Ni-rich LiNi0.91Co0.06Mn0.03O2 cathode material to enhance its cyclability and rate performance. The process is carried-out by achieving dual benefits, reduction of residual lithium compounds by converting them into Li3PO4 coating material. The 0.1 mol.% Li3PO4 (LiP) sample exhibits a capacity retention of 82% while the pristine NCM shows only 68.1% after 100 cycles. In addition, the LiP-0.1 NCM delivers high discharge capacities (161.9 mAh g−1 at 3C, 144.3 mAh g−1 at 4C and 94.6 mAh g−1 at 5C) as compared to the pristine NCM (129.3 mAh g−1 at 3C, 67.4 mAh g−1 at 4C and 33.4 mAh g−1 at 5C) in the voltage range of 3.0–4.3 V. In addition, the irreversible phase transition has also suppressed in the coated sample which is confirmed by cyclic voltammetry. Our study suggests that Li3PO4 coating reduces the polarization and acts as protecting layer between the electrode and electrolyte that results in the superior electrochemical performance.