Upcycling the Spent Graphite Anode Into the Prelithiation Catalyst: A Separator Strategy Toward Anode‐Free Cell Prototyping

Abstract

The substantial manufacturing of lithium‐ion batteries (LIBs) requires sustainable, circular, and decarbonized recycling strategies. While efforts are concentrated on extracting valuable metals from cathodes using intricate chemical process, the direct, efficient cathode regeneration remains a technological challenge. More urgently, the battery supply chain also requires the value‐added exploitation of retired anodes. Here, a “closed‐loop” approach is proposed to upcycle spent graphite into the prelithiation catalyst, namely the fewer‐layer graphene flakes (FGF), upon the exquisite tuning of interlayer spacing and defect concentration. Since the catalytic FGF mitigates the delithiation energy barrier from calcinated Li5FeO4 nanocrystalline, the composite layer of which cast on the polyolefin substrate thus enables a customized prelithiation capability (98% Li+ utilization) for the retired LiFePO4 recovery. Furthermore, the hydrophobic polymeric modification guarantees the moisture tolerance of Li5FeO4 agents, aligning with commercial battery manufacturing standards. The separator strategy well regulates the interfacial chemistry in the anode‐free pouch cell (LiFePO4||Cu), the prototype of which balances the robust cyclability, energy density up to 386.6 Wh kg−1 as well as the extreme power output of 1159.8 W kg−1. This study not only fulfills the sustainable supply chain with graphite upcycling, but also establishes a generic, viable protocol for the anode‐free cell prototyping.