Effects of PVdF Binder Molecular Weight and Active Material Morphology on Processing, Structure, and Performance of LiNi 0.6 Mn 0.2 Co 0.2 O 2 ‐Based Positive Electrodes

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Polyvinylidene difluoride (PVdF) is the most common binding agent for positive electrodes in lithium ion batteries. However, its processing solvent N‐ methyl‐2‐pyrrolidone (NMP) poses safety and environmental risks and regulations increasingly demand its reduction. Adapting the binder is a promising approach to decrease material and energy consumption. This study examines how the molecular weight of PVdF affects electrode paste properties, composite electrode properties, and electrochemical performance of LiNi 0.6 Mn 0.2 Co 0.2 O 2 ‐based electrodes, while also considering active material particle morphology. The impact of the molecular weight on electrode paste properties was more pronounced for single‐crystalline than for polycrystalline active material particles, attributed to the narrower particle size distribution of the single crystalline particles. Among the investigated binders, low‐molecular‐weight PVdF showed the most promising results for polycrystalline systems. During processing, the solid content was increased to 82%, reducing the NMP mass fraction within the wet electrode paste by 33%. Electrodes based on the low‐molecular‐weight binder exhibited high porosities, while maintaining sufficient particle–particle contact, yielding high rate capability. By adjusting the solid content and utilizing low‐molecular‐weight binder, cycle‐life was notably extended. Overall, this study demonstrated the potential of using low‐molecular‐weight PVdF, enabled substantial NMP reduction in cathode production, thus promoting safer and more environmentally friendly battery manufacturing.

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