Upcycling Spent Graphite into Fast-Charging and Sustainable Anodes via Interfacial Catalytic-Percolative Engineering

Abstract Driven by the urgent requirements for sustainable lithium-ion batteries, the re-utilization of spent graphite featuring accumulated defects and interfacial degradation is shifting from simple compositional recovery toward functional reconfiguration. Herein, an effective interfacial strategy is proposed to upcycle spent graphite into recycled graphite encapsulated by amorphous Al2O3 nanonetworks (denoted as ARG) via a facile low-temperature heat treatment. According to experimental and theoretical calculation results, the amorphous Al2O3 coating containing Lewis-acidic Al3+ sites can strongly interact with electrolytic solvent molecules to reduce the Li+ desolvation energy barrier, catalyzing the formation of a LiF-rich SEI layer with improved electronic conductivity and reduced interfacial charge transfer resistance. Moreover, thin Al2O3 interphase, featuring negative Li+ adsorption energy, couples effectively with inherent bulk defects, thereby enabling substantially enhanced Li+ trapping and storage via multidimensional ion diffusion pathways. Contributing to the interfacial “catalytic-percolative” regulation, ARG anode exhibits an ultra-high capacity (394 mAh g–1), superior rate performance and excellent cycling stability even at 4 C, providing novel insights into constructing fast-charging and durable upcycled graphite with significant economic and ecological value.