Lithium-ion battery : Rebirth of critical battery components by recovering and reusing LiFePO₄ cathode and separator

The rapidly expanding lithium-ion battery market, triggered by the growth of portable and electric consumer electronics, poses enormous challenges to recycling and end-oflife battery disposal. It is noted to many other materials used as positive electrode, lithium iron phosphate (LFP) possesses the benefits of thermal stability, high cycle life, and safety and therefore has been widely utilized under the risk of enormous scrapping. This thesis explores a more sustainable approach to recycling end-of-life LFP batteries by regenerating the cathode and separator. This approach, which focuses on direct regeneration, avoids discharging and pulverization-mandatory steps in common battery recycling processes-resulting in reduced time, energy consumption, waste generation, and cross-contamination. LFP recovery involves calcination, lithiation, and reusing the recycled materials while the separator recycling involves ultrasonic in water media. The structural and morphological changes of recycled materials were investigated by X-ray diffraction, scanning electron microscopy and then Fourier transform infrared spectra demonstrated the functional groups. In additional, long-term charge-discharge and cyclic tests evalutated the electrochemical performance. The results showed that the regenerated LFP battery had significantly increased discharge capacity of more than 105 mAh g-1from an initial value of 19.2 mAh g-1for the spent battery. They also had stable cyclic performance and reversibility. For the separator, the optimal ultrasonicating time of 5 minutes also maintained the structural integrity while effectively removing surface residues.