Upcycling of plastic waste into carbon nanotubes as efficient battery additives

Carbon nanotubes (CNTs) were produced from waste face masks and non-recyclable mixed plastic waste via pyrolysis-chemical vapor deposition (CVD). The yield and properties of the prepared CNTs depended on the feedstock and catalyst used. CoMo/MgO and FeMo/MgO were proven suitable catalysts for producing few-walled and multi-walled CNTs, respectively, regardless of the feedstock. Both mask waste and the FeMo/MgO catalyst led to excellent carbon yield (516.7 wt%) and CNT purity (97.9 wt%). The resulting CNTs were mixed with LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) active material and poly(vinylidene fluoride) binder to fabricate cathodes. Electrochemical measurements showed that CNTs grown on the FeMo/MgO catalyst outperformed commercial carbon black and CNTs. C₁-C₃ hydrocarbons and H₂ present in the plastic pyrolysis gas can be directly used for CNT production without gas separation or purification, therefore, the proposed pyrolysis-CVD process is favorable for efficient plastic upcycling and advanced battery applications.