Transforming spent lithium iron phosphate cathodes and waste plastics into high-performance sodium-ion battery anodes via co-pyrolysis

Abstract

With the increasing prevalence of lithium iron phosphate (LFP) batteries and waste ultra-high molecular weight polyethylene (UHMWPE) products, advanced recycling strategies have garnered significant interest in sustainable resource development. However, challenges such as cumbersome procedures and improper hazardous waste disposal must be effectively addressed. In this work, we propose a simplified and economical method for converting waste LiFePO₄ cathode waste to a novel sodium-ion battery anode material. By leveraging waste plastics to catalyze the production of carbon nanotubes (CNTs) at high temperatures, a novel anode material, R-Fe₂P/CNT, was fabricated, which exhibits excellent long-term cycling stability (capacity retention rate of 86.36 % at 1.0 A g⁻¹ after 600 cycles) and rate capability. Furthermore, density functional theory calculations showed improved sodium adsorption and enhanced electronic conducitivity in R-Fe₂P/CNT composites. This strategy effectively recycles the valuable components of used batteries and plastics, offering a new "treating waste with waste" concept for the preparation of functional materials.