Sustainable Recovery and Reuse of Hard Carbon From Scrap and End‐of‐Life Sodium‐Ion Batteries

Abstract

Abstract As Sodium‐ion battery (SIB) technology progresses toward commercial viability, sustainable end‐of‐life (EOL) management is critical. Methods for recycling key components such as hard carbon (HC), a negative electrode material, remain underexplored. This study introduces a direct and efficient recycling approach for HC from production scrap and EOL cells using “ice‐stripping” followed by a low‐temperature binder negation at 300 °C under nitrogen. The effects of temperature on HC structural integrity and electrochemical performance are comprehensively characterized using XRD, Wide‐Angle X‐ray Scattering (WAXS), and XPS. Heating above 400 °C induces irreversible damage to HC's graphene layers and modifies the carbon surfaces, resulting in poor electrochemical performance. However, HC reclaimed at 300 °C retains near‐pristine electrochemical performance, with capacities of 243 mAh g⁻¹ (scrap) and 228 mAh g⁻¹ (EOL) after 50 cycles. Full‐cell configurations demonstrates robust cycling stability, with 86% and 89% capacity retention after 200 cycles for HC derived from scrap and EOL cells, respectively. This work highlights the potential of lower‐temperature, direct recycling to enable a circular economy for SIBs. The findings set a benchmark for developing sustainable recycling methods for HC and other SIB components.