Optimization of the hydrothermal process for simultaneous LiNi0.5Co0.2Mn0.3O2 regeneration and polyvinylidene fluoride (PVDF) decomposition

Nickel‑cobalt‑manganese (NCM) ternary lithium-ion batteries (LIBs), widely utilized in new energy vehicles , inevitably face retirement after prolonged use due to capacity decay and performance degradation . These batteries consist of lithium, nickel, cobalt, manganese, and other metals and organic compounds. Mishandling these batteries can lead to significant environmental harm. Therefore, recycling and reprocessing used ternary LIBs is essential. The conventional hydrothermal method for cathode repair and regeneration has demonstrated broad applicability and remarkable effectiveness in recovering ternary LIBs, indicating promising prospects for application. However, high hydrothermal temperatures and fluorine contamination hinder its practical implementation. This study optimized the traditional hydrothermal method for cathode repair and regeneration to address these challenges by utilizing a reducing environment facilitated by glucose, which lowers the activation energy barrier and reduces the hydrothermal temperature. Additionally, the optimized method degrades the binder polyvinylidene fluoride (PVDF) during the repair and regeneration process, effectively preventing fluorine contamination. Conditional experiments and quantitative analyses using Raman spectroscopy were conducted to investigate the degradation efficiency and pathways of PVDF. The regenerated LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM523) polycrystalline particles were successfully restored in morphology and structure, exhibiting good specific capacity and cycling stability. This was confirmed through scanning electron microscopy (SEM), laser particle size analysis , X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and other analytical methods, alongside electrochemical tests. This study presents a sustainable, cost-effective, and environmentally friendly solution for efficiently recycling and reprocessing ternary LIBs. • Polyvinylidene fluoride (PVDF) degradation. • Hydrothermal repair of NCM523 cathode with simultaneous degradation of PVDF. • Achieving hydrothermal repair of LiNi0.5Co0.2Mn0.3O2 (NCM523) at lower temperatures.