Direct Regeneration of Spent Graphite Electrodes Using an Organic Solvent-Free Approach: Evaluation of Aqueous- and Rapid Thermal Processing-Assisted Black Mass Delamination

Sustainable recycling of graphite anodes is critical for enabling closed-loop lithium-ion battery manufacturing, yet most direct recycling methods rely on organic solvents and corrosive acid treatments that increase costs and environmental impacts. Herein, we evaluate an organic solvent-free, direct recycling strategy that combines aqueous graphite recovery with boric acid-assisted regeneration. Water-based delamination of graphite black mass was investigated using two representative commercial end-of-life graphite anodes and a commercially manufactured uncycled graphite anode. The effectiveness of aqueous separation of the black mass from the Cu current collector was investigated along with rapid thermal processing (RTP), which has been proposed to improve graphite recovery through binder degradation. Both methods resulted in effective graphite recovery despite impurities originating from ceramic-coated separators, Ti-containing additives, and current collector corrosion. However, delamination of RTP-treated spent anodes was more difficult than pristine anodes, requiring pre-RTP washing and ultrasonication for efficient graphite recovery. Boric acid treatment followed by calcination at 1050 °C increased the degree of graphitization for all spent graphite samples while removing residual surface species and trapped lithium. Electrochemical testing showed that the regenerated graphite largely recovered its capacity and electrochemical activity, although residual metallic impurities may limit long-term cycling stability. Overall, aqueous delamination combined with boric acid-assisted regeneration provides an effective and more sustainable route for graphite recycling by eliminating organic solvents and strong mineral acids while preserving favorable structural and electrochemical properties. This process offers a promising pathway for scalable, environmentally responsible recovery of graphite from end-of-life lithium-ion batteries.