Fluorine‐Free Lithium‐Ion Batteries: A Working Alternative

Current lithium ion batteries contain fluorinated electrolytes and binders to enhance their stability over time. However, these fluorinated materials also pose ecological risks during manufacturing, disposal and recycling after use. In this perspective the comparison of completely fluorine-free working battery designs and fluorinated designs shows that they can have very similar cycling performance, providing pathways to omit fluorine use.

Current commercial battery designs contain fluorinated materials as binders and electrolyte salts to ensure high electrochemical and thermal stability. Upcoming regulations in Europe and the US restrict the manufacturing of such materials, as their persistence in drinking water and soil can cause long-term ecological harm. In this perspective, a completely fluorine-free battery design that has similar performance compared to commercial standards, while using aqueously processed LiNi_0.8Mn_0.1Co_0.1O₂ (NMC811) and graphite as cathode and anode active materials, respectively, is showcased. The cell shows 98% retained capacity after 600 cycles at room temperature, indicating good stability of active material with nonfluorinated binders. The charge rate performance (69% retained capacity at 1C, 1.5 mAh cm⁻²) can be improved by combining two fluorine-free salts (67% retained capacity at 1C with 2.5 times the loading, 3.3 mAh cm⁻²). This work illustrates that fluorine-free cell designs show good battery performance over a wide potential window.

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