Re-synthesis and Electrochemical Characteristics of LiFePO₄Cathode Materials Recycled from Scrap Electrodes

Abstract

This paper describes an environmentally friendly process for the recovery of LiFePO 4 cathode materials from scrap electrodes by a simple thermal treatment method. The active materials were easily separated from the aluminum substrate foil and polymeric binders were also decomposed at different temperatures (400 o C, 500 o C, 600 o C) for 30 min under nitrogen gas flow. The samples were characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM), Raman spectroscopy, Thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The electrochemical properties of the recycled LiFePO 4 cathode were evaluated by galvanostatic charge and discharge modes. The specific charge/discharge capacities of the recycled LiFePO 4 cathode were similar to those of the original LiFePO 4 cathode. The LiFePO 4 cathode material recovered at 500 o C exhibits a somewhat higher capacity than those of other recovered materials at high current rates. The recycled LiFePO 4 cathode also showed a good cycling performance.

Progress and Status of Hydrometallurgical and Direct Recycling of Li-Ion Batteries and Beyond

“…These results were in agreement with those reported by Zucolotto et al who suggested a two steps mechanism starting with the evaporation of HF followed by carbon chain scission [96]. Beyond the decomposition of the binder, thermal treatment allows the destruction of other organic contaminants, recrystallization of the active material, and regeneration of the carbon coating [69,97,98]. According to Kim et al, the carbonization of the binder during the thermal treatment of LFP black mass in N 2 atmosphere increased the electrical conductivity of the active material and enhanced its electrochemical performance [69].…”

“…Similar thermal reactivation processes were explored for LFP batteries, notably by Kim et al [69]. In the process of Kim et al, after opening of batteries and sorting their components, the cathode was submitted to thermal treatment at 500 • C under nitrogen flow.…”

“…Pretreatment processes could be grouped into three categories: Physical, chemical, and thermal [69,70]. More specifically, the typical pretreatment steps could be identified according to the list below; these steps could be used separately or could be combined: Washing.…”

“…Beyond the decomposition of the binder, thermal treatment allows the destruction of other organic contaminants, recrystallization of the active material, and regeneration of the carbon coating [69,97,98]. According to Kim et al, the carbonization of the binder during the thermal treatment of LFP black mass in N 2 atmosphere increased the electrical conductivity of the active material and enhanced its electrochemical performance [69]. This process will be further discussed in the section on direct recycling.…”

Three-dimensional embroidered current collectors for ultra-thick electrodes in batteries

“…15 The use of SBR as watersoluble binder in LiFePO 4 cathode material as a substitute of PVdF binder has already been reported in the literature. [16][17][18] The recipe used in this work is based on descriptions in the literature. 19 In future work, the recipes for the cathode will be further optimized.…”