Valorization of hazardous graphite from black mass (NMC 111) of lithium-ion battery recycling via KOH activation for functional carbon design

The rapid adoption of lithium-ion batteries (LiBs) in energy storage has driven research into resource recovery. This study converts hazardous graphite from the black mass (NMC 111) of spent LiBs into functional activated carbons (ACs) via KOH activation. Tailoring the synthesis at 800 °C and a graphite-to-KOH ratio of 1:6 produced AC with a surface area of 678 m²/g and a total pore volume of 0.442 cm³/g. The material showed a balanced micropore–mesopore structure, with micropores contributing 53 % of the total pore volume. The material showed a balanced micropore–mesopore structure, with micropores contributing 53 % of the total volume. XRD confirmed preserved graphitic crystallinity with a dominant (002) peak at 26.52°. Raman spectroscopy indicated increased defect density (I_D/I_G = 1.053), facilitating porosity formation. SEM and TEM revealed a transition from smooth graphite layers to a porous, defect-rich structure, with TEM highlighting mesopore-like voids and distorted graphitic domains featuring edge defects. XPS identified surface modifications, including a higher proportion of sp² carbon and oxygen-containing groups (C–O, C=O, C-OH, CO₃²⁻). TGA demonstrated stability (∼900 °C) under inert conditions and enhanced reactivity in oxidative environments. This work valorizes LiB-derived graphite waste into ACs, supporting circular economy strategies and demonstrating potential for industrial scalability.