Achieving Waste-Valorized Anode Materials for Li-Ion Batteries by Surface Engineering of Recycled Graphite from Spent Zn–C Batteries

The conventional recycling of Zn-C batteries typically relies on either the disposal into landfills or the direct incineration, yielding adverse pollution and unnecessary carbon emissions to the environment and atmosphere.Even though one of the main components in the batteries, the carbon rod could serve as a valuable secondary carbon source.Herein, we present a sustainable method to recycle waste Zn-C battery graphite as high-performance lithium-ion battery (LiBs) anodes through thermal and alkaline (KOH) treatments.Extensive structural and surface analyses revealed that the optimized treatment (RG H-K) removed metal impurities and beneficial surface activation through defect generation and functional group stabilization.This facilitated lithium-ion transport kinetics along the activated surface architecture and stabilized solid-electrolyte interphase (SEI) formation.Electrochemical measurements showed excellent performance in which the specific capacity of RG H-K achieved 364.51 mAh/g at 0.2C and 255.88 mAh/g at 5C, along with stable long-term cycling (>200 cycles) at 1C, maintaining a capacity of 350 mAh/g.These findings highlight the potential of engineered surface modification in upcycling waste graphite into high-performance, environmentally sustainable LIB anodes.