A Facile, Environmentally Friendly, and Low-Temperature Approach for Decomposition of Polyvinylidene Fluoride from the Cathode Electrode of Spent Lithium-ion Batteries

Abstract

High-temperature heat treatment (500 °C) is an effective measure for decomposing the organic binder polyvinylidene fluoride (PVDF) in the cathode electrode of spent lithium-ion batteries (LIBs). However, the resulting volatilization of hydrogen fluoride not only causes equipment corrosion but also creates a potential environmental hazard. This study proposes the use of calcium oxide (CaO) as a reaction medium to eliminate the environmental impact of the thermal decomposition of PVDF in the cathode electrode of spent LIBs. The results show that with CaO as the reaction medium, the PVDF in the cathode electrode can be thermally decomposed at the lower temperature of 300 °C, solving the problem of separation of the cathode materials and Al foil; the separation efficiency of the cathode materials surpassed 97.1 wt %. Further characterization results confirmed that the PVDF covering the surface of the cathode electrode can be effectively decomposed and absorbed by CaO in situ, and no release of hydrogen fluoride was detected. These results indicate that the use of CaO can reduce the processing cost and avoid the release of hydrogen fluoride, providing both economic and environmental benefits. This study therefore provides a potential technical approach for the green recycling of spent LIBs.