Sustainable Upcycling of Biomass Waste into Self‐Supporting Carbon/Red Phosphorus Hybrid Anodes for High‐Energy Sodium‐Ion Batteries

Tackling the dual challenges of global resource circularity and sustainable energy storage, this study pioneers a novel strategy for converting waste biomass (discarded cloth and paper) into high‐performance composite anodes for sodium‐ion batteries (SIBs) through a dual‐engineering approach. Employing a gradient carbonization strategy, 3D porous carbon matrices retaining the intrinsic hierarchical architecture of the precursors are fabricated. Notably, the waste paper‐derived carbon framework exhibits exceptional self‐supporting properties. Subsequent vapor deposition enables the homogeneous encapsulation of red phosphorus (RP) throughout the carbon skeleton, yielding a stable Carbon@RP composite. Electrochemical evaluations demonstrate that the paper‐derived Carbon@RP anode delivers a remarkable reversible capacity of 813.5 at 0.5 mA cm −2 . Mechanistic studies reveal that the paper‐inherited “book‐like” lamellar channel structure facilitates deep phosphorus infusion. This work establishes a closed‐loop paradigm integrating “waste‐to‐energy storage” conversion, offering a practical and scalable pathway toward eco‐friendly, high‐energy‐density SIBs for next‐generation grid‐scale renewable energy systems.