Spider web-structured Sb2MoO6@C@CNF composites with conductive-stable dual carbon skeletons toward durable sodium-ion batteries

Abstract

Antimony (Sb)-based anodes for sodium-ion batteries (SIBs) face critical challenges in reconciling high theoretical capacity (∼660 mAh g⁻¹) with structural degradation caused by severe volume expansion (∼400%) during cycling. Herein, a spider web-inspired Sb₂MoO₆@C@CNF composite is synthesized through an integrated hydrothermal-electrospinning strategy, featuring a dual-carbon architecture where polyacrylonitrile (PAN)-derived carbon nanofibers (CNFs) interweave with polypyrrole (PPY)-carbonized N-doped conductive networks. This hierarchical design synergistically enhances electron transport kinetics and accommodates mechanical stress, as evidenced by the anode delivering a reversible capacity of 210 mAh g⁻¹ after 5000 cycles at 5 Å g⁻¹ (96.3% capacity retention). The dual-carbon confinement mechanism effectively restricts Sb₂MoO₆ nanoparticle pulverization while maintaining robust electrode integrity, offering a universal strategy for alloy-type anode stabilization.