ABSTRACT 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 FePO 4 in spent lithium‐iron phosphate (LFP‐Spe). The newly formed FeF 2 , 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 FeF 2 (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.
M et al. (2026) studied this question.