Nanoarchitectonics for Green Upgrading Spent Battery With PFAS via One-Pot Mechanochemistry

Using one waste to upgrade another through a simple process is a promising strategy for the circular economy. Herein, spent batteries are upgraded using per- and polyfluoroalkyl substances (PFAS) via a one-pot mechanochemical route without involving any solvents, gases, byproducts, or heating. A facile ball-milling process drives the cleavage of strong C─F bonds in PFAS while simultaneously enabling the selective fluoridation of inactive FePO₄ in spent lithium-iron phosphate (LFP-Spe). The newly formed FeF₂, together with the unreacted lithium-iron phosphate (LFP), delivers an impressive capacity of 307.3 mAh g⁻¹ at 1C, far exceeding the theoretical capacity of LFP (169.8 mAh g⁻¹, 1 e) and surpassing the one-electron theoretical capacity of FeF₂ (285 mAh g⁻¹). Meanwhile, carbon derived from PFAS forms an in situ conductive coating on the composite surface, which enables the cathode to retain 92.7% of its initial capacity after 1000 cycles at 5C. Additionally, mechanochemically activated carbon appears to provide a reducing environment and to participate in partial interfacial coupling with phosphate-containing species. This work shows that solid‑state nanoarchitectonics can serve as a promising route to construct functional electrode architectures directly from multiple wastes, offering a new upcycling direction that turns different wastes into wealth.