Graphene-interconnected Bi@Bi₂O₂CO₃ heterostructures with enhanced electrochemical Kinetics Stability for Supercapacitors

Despite their high theoretical capacity, Bi-based anodes are plagued by sluggish charge-transfer kinetics and severe structural degradation originating from poor electrical conductivity and repeated volume variation during alloying/dealloying. Herein, a graphene nanoribbon-interconnected Bi@Bi₂O₂CO₃ heterostructure (B/BOC-GR_0.1) is designed to simultaneously establish a continuous conductive network and reinforce the heterointerface. The Bi₂O₂CO₃ shell effectively accommodates cyclic strain and stabilizes the electrode architecture, while graphene nanoribbons strengthen interfacial electronic coupling and accelerate electron transport, thereby synergistically promoting reaction kinetics and structural robustness.As a result, B/BOC-GR_0.1 delivers 1560 C g^-1 at 1 A g^-1 and retains 795 C g^-1 at 50 A g^-1, greatly surpassing those of Bi anodes (623 C g^-1 at 1 A g^-1, 281 C g^-1 at 50 A g^-1). Moreover, after 5000 cycles at 10 A g^-1, B/BOC-GR_0.1 maintains approximately 90% of its initial capacity. The construsted asymmetric supercapacitor achieves an energy density of 70 Wh kg^-1 at a power density of 752 W kg^-1, highlighting the potential of the designed heterostructure for advanced electrochemical energy-storage applications.