Closed-loop graphite recycling from the manufacturing scrap graphite by sulfuric acid leaching combined with...

The rapid expansion of lithium-ion battery (LIB) manufacturing generates large quantities of manufacturing scrap graphite. Recycling these industrial offcuts can alleviate the looming shortage of natural graphite and significantly reduce anode material costs. In this work, we report a purification strategy that combines sulfuric acid leaching with low-temperature oxidation to regenerate scrap graphite (SG). Sulfuric acid selectively removes metallic impurities, while mild oxidation eliminates organic binders. Leaching in 4 mol·L^-1 H₂SO₄ at 90 °C for 2 h with a liquid-to-solid ratio of 10 mL·g^-1, followed by oxidation at 350 °C for 1 h under O₂, produces regenerated graphite (RG) with a purity of 99.58 wt%. The RG delivers a reversible capacity of 423.8 mAh·g^-1 at 0.5C and retains 97% of its capacity after 200 cycles. The enhanced electrochemical performance was attributed to the impurity removal and moderate surface oxygen functionalization, which collectively promote rapid Li⁺ transport and interfacial stability. This work provides an environmentally friendly and practical pathway for the closed-loop recycling of graphite anodes in LIB manufacturing.