Influence of the LiFePO4/C coating on the electrochemical performance of Nickel-rich cathode for lithium-ion batteries

LiFePO4/C (LFP/C)-coated LiNi0.8Co0.1Mn0.1(NCM811) was prepared by a simple ball milling method (400 rpm for 4 h), and the influence of different coating amounts of LFP/C on the electrochemical performance of NCM811 was studied in detail. When the LFP/C coating amount was 1 wt%, the material maintained good electrochemical cycling stability and rate performance. The capacity retention of NCM811 @ 1LFP/C after 300 cycles was 61.6% at 25 ℃, which was significantly better than the corresponding value of 48.63% of NCM811. Simultaneously, the high temperature (55 ℃) and high pressure (2.8–4.5 V) cycling stability performance of NCM811 @ 1LFP/C was also better than for uncoated materials. The EIS results showed that the 1LFP/C modification effectively reduced RSEI (from 46.37 to 32.13 Ω) and Rct (from 155.9 to 113.5 Ω), which was beneficial for the interface charge transfer of electrons and Li+ ions, consistent with the CV analysis. The XRD, XPS, and FESEM results indicated that the coating layer suppressed the changes in the NCM811 particle macro-volume and reduced the side reactions, improving the electrochemical performance of Nickel-rich layered materials.