Influence of Phosphate Surface Coating on Performance of Aqueous‐Processed NMC811 Cathodes in 3 Ah Lithium‐Ion Cells

Abstract Aqueous processing of state‐of‐the‐art cathode materials for lithium‐ion batteries like LiNi0.8Mn0.1Co0.1O2 (NMC811) has evolved as a more sustainable and cost‐effective alternative to the conventional 1‐methyl‐2‐pyrrolidone‐based process. However, the implementation of aqueous processing is challenging due to the water sensitivity of nickel‐rich layered oxides. This study investigates the influence of a phosphate‐based NMC811 surface coating on the performance of aqueous‐processed NMC811 cathodes in 3 Ah cells. The results show that the cells with phosphate‐coated NMC811 outperform those with uncoated NMC811, i. e., they exhibited higher initial capacity and improved capacity retention during cycling. Post‐mortem characterization techniques reveal that the phosphate coating limits the lithium loss during aqueous cathode manufacturing and further reduces side reactions during cycling, resulting in a smaller increase of cell impedance.