Abstract
The sustainable management of spent cathode carbon (SCC), a hazardous solid waste from the primary aluminum industry, represents a significant environmental challenge. Herein, we report a one-step molten salt electrochemical strategy for the simultaneous purification and graphitization of SCC, transforming it directly into a high-value cathode material for aluminum-ion batteries (AIBs). The harmful fluoride and cyanide impurities were efficiently removed through electrochemical methode in a molten CaCl₂ at 850 °C. The resulting electrolyzed spent cathode (ESC) exhibited a highly graphitized structure with an expanded interlayer spacing (0.3356 nm), and the degree of graphitization is as high as 97.6%. When evaluated as positive electrode materials in an AIBs with an ionic liquid electrolyte (AlCl₃/[EMIm]Cl), the ESC electrode delivered a remarkable specific capacity of 90 mAh g−1 at 0.1 A g−1. This work pioneers a sustainable and economic path for the valorization of hazardous aluminum industry waste into functional energy storage materials, contributing to a circular economy.