Reconciling PTFE Fibrillation and Cycling Stability in Dry‐Process NCM Cathodes via Polycrystalline‐Single‐Crystal Particle Grading

ABSTRACT Dry‐process electrode technology is an important route for next‐generation lithium‐ion battery (LIB) manufacturing because it eliminates solvent use during electrode production. However, the influence of active material particle characteristics on PTFE fibrillation and electrode design remains insufficiently understood. Here, polycrystalline and single‐crystal NCM811 particles are used as model materials, and their nanoscale surface morphologies are quantified by atomic force microscopy. Polycrystalline particles exhibit a higher mean surface roughness than single‐crystal particles, with Ra values of 60.18 and 32.77 nm, respectively. Their different fibrillation behaviors are analyzed by considering particle morphology, size, and contact geometry. Polycrystalline particles favor PTFE fibrillation but are more susceptible to cycling‐induced structural degradation, whereas single‐crystal particles provide greater structural stability but lower fibrillation capability. Based on these complementary characteristics, a polycrystalline‐single‐crystal grading strategy is proposed. Among the three compositions tested, PS91 containing 10 wt.% single‐crystal particles achieves the best balance between transport kinetics and cycling stability, retaining a discharge capacity of 152.04 mAh g −1 after 50 cycles at 0.33C. Its H1‐M peak shift is 67% smaller than that of PS10, while post‐mortem cross‐sectional SEM reveals less severe particle cracking. A discrete element model shows how mixing speed and particle size ratio affect uniformity, supporting process optimization.