Abstract
Spent LiNi(x)Co(y)Mn(z)O(2) (x + y + z = 1) and polyethylene terephthalate are major solid wastes due to the growing Li-ion battery market and widespread plastic usage. Here we propose a synergistic pyrolysis strategy to recover valuable metals by thermally treating LiNi(1/3)Co(1/3)Mn(1/3)O(2) and polyethylene terephthalate. With polyethylene terephthalate assistance, LiNi(1/3)Co(1/3)Mn(1/3)O(2) decomposes at 400 °C, and fully converts to Li(2)CO(3), MnO, and Ni-Co alloy at 550 °C within 30 min, using a 1.0:0.3 mass ratio of LiNi(1/3)Co(1/3)Mn(1/3)O(2) to polyethylene terephthalate. Furthermore, density functional theory calculations confirm the preference for O-Li bonding. Surface adsorption and free radical/gaseous reduction reactions explain the role of polyethylene terephthalate in promoting lattice destruction. The complete decomposition facilitates efficient post-treatment, achieving over 99% recovery of Li, Ni, Co, and Mn via water washing. Regenerated LiNi(1/3)Co(1/3)Mn(1/3)O(2) was synthesized by using recovered Li- and transition metal-containing products as feedstocks. This study provided a chemical-free, energy-saving, and scalable recovery strategy while addressing polyethylene terephthalate waste minimization.