Aqueous Processing of Ni-Rich NMC Cathodes: Degradation Mechanisms, Mitigation Strategies, and Manufacturing Outlook

This is the authors' abstract. We don't add key points for this paper.

Aqueous processing can eliminate N-methyl-2-pyrrolidone (NMP) and polyvinylidene fluoride (PVDF) from the manufacture of Ni-rich layered-oxide cathodes. Yet water alters powder surface chemistry, slurry alkalinity, aluminium current collectors, coating quality, and cyclable lithium inventory. This mini-review treats these effects as a coupled manufacturing problem. It distinguishes rapid dissolution of residual LiOH/Li₂CO₃ from lattice Li⁺/H⁺ exchange. It then examines how alkalisation, aluminium corrosion, H₂ evolution, surface reconstruction, and drying defects interact. Four control families are compared: surface stabilisation, pH-control additives, functional binders, and integrated formulation and process control. The comparison considers composition, formulation, production scale, cell format, cycling, reported cost, and matched controls. A separate route analysis contrasts aqueous coating with PVDF/NMP coating and solvent-free dry-electrode manufacture. Pilot evidence includes 10-L slurry mixing, 140-m double-sided coating, 3.5-Ah 21700 cells, and about 80% pouch-cell retention after 1000 cycles. Recent studies also report high-loading dry electrodes, multifunctional aqueous binders, and process-specific energy or cost reductions. These results are promising but not directly interchangeable. Lithium-metal half-cells can mask lithium-inventory loss, and study-specific techno-economic models do not represent every plant. Priority evidence gaps are matched full-cell validation, line-scale yield and defect statistics, recycling material balances, and repeated manufacture, use, recycling, and remanufacture.