Mass Production of Waste PVC‐Mediated Bamboo‐Derived Hard Carbon for Ultra‐Long Life Sodium Storage

ABSTRACT The practical application of sodium‐ion batteries (SIBs) hinges on high‐performance hard carbon (HC) anodes. Biomass‐derived carbons are low‐cost yet commercially uncompetitive due to inferior performance. Herein, we report a scalable dual‐functional strategy that hybridizes pre‐carbonized bamboo grains with waste polyvinyl chloride (PVC) to construct a structurally optimized HC. This PVC‐mediated approach moves beyond physical coatings of conventional pitch by enabling chemical reconstruction of the carbon architecture. During pyrolysis, vinyl radicals from PVC crosslink with fine bamboo‐derived carbon species to form a low‐defect, highly conductive soft surface carbon layer, while simultaneously elevating the concentration of carbon‐centered radicals to promote closed‐pore formation. This process ultimately yields a functional‐partitioning HC featuring abundant internal closed pores and surface sp ² ‐enriched graphitic domains, which endows the anode with exceptional high‐rate long‐cycle stability. The resulting HC achieves an initial Coulombic efficiency (ICE) of 90.3% and a reversible capacity of 378.5 mAh g ⁻¹ . Notably, it retains 93% of its capacity after 8100 cycles at 1.5 A g ⁻¹ , with a capacity decay of only 0.00086% per cycle. Importantly, kilogram‐scale synthesis is achieved, with the material outperforming commercial HC electrochemically. This facile strategy offers insights into the rational design of ideal HC architectures.