Dual‐Interfering Chemistry for Soft‐Hard Carbon Translation toward Fast and Durable Sodium Storage

Abstract

AbstractDirect pyrolysis of low‐cost and resource‐abundant pitch generally produces highly graphitized soft carbon, showing low reversible capacity and a negligible charge‐discharge plateau owing to its unsuitable microstructure for sodium storage. Herein, for the first time, an innovative dual‐interfering chemistry strategy is proposed to solve the soft‐hard carbon translation challenge. Multifunctional zinc gluconate generates dual‐mechanism interference upon decomposition and successfully regulates pitch pyrolysis: 1) the gas decomposition products (carbon oxides) may consume excess hydrogen to realize fusion‐to‐solid‐state pyrolysis of pitch, hindering microcrystalline ordering; 2) the solid compounds (i.e., organic zinc salt and ZnO nanoparticles) not only weakens strong π–π interactions between the aromatic chains of pitch but also introduces abundant closed pores into the carbon matrix. The optimized pitch‐derived hard carbon (PZHC 450–1200) shows an absorption‐insertion‐pore filling sodium storage mechanism after microstructure conversion from graphitic structure to a pore‐rich and turbostratic structure. As a result, the PZHC 450–1200 exhibits a high reversible capacity of 320 mAh g−1 at 30 mA g−1 with a more than twofold‐enhanced low‐voltage plateau capacity ratio, and outstanding rate capability that outperforms almost all previously reported pitch‐derived carbons. The concept of dual‐interfering chemistry contributes to achieving low‐cost and high‐performance hard carbon for fast and durable sodium storage.